diff --git a/R/find_parameters_mixed.R b/R/find_parameters_mixed.R
index 6bf833fcc..6ff7e02b6 100644
--- a/R/find_parameters_mixed.R
+++ b/R/find_parameters_mixed.R
@@ -144,14 +144,11 @@ find_parameters.nlmerMod <- function(x, effects = "all", component = "all", flat
 }
 
 
-#' @rdname find_parameters.glmmTMB
 #' @export
-find_parameters.hglm <- function(x,
-                                 effects = c("all", "fixed", "random"),
-                                 component = c("all", "conditional", "dispersion"),
-                                 flatten = FALSE,
-                                 ...) {
-  effects <- match.arg(effects)
+find_parameters.hglm <- function(x, effects = "all", component = "all", flatten = FALSE, ...) {
+  effects <- validate_argument(effects, c("all", "fixed", "random"))
+  component <- validate_argument(component, c("all", "conditional", "dispersion"))
+
   fe <- x$fixef
   re <- x$ranef
 
@@ -173,13 +170,9 @@ find_parameters.hglm <- function(x,
 }
 
 
-#' @rdname find_parameters.glmmTMB
 #' @export
-find_parameters.merMod <- function(x,
-                                   effects = c("all", "fixed", "random"),
-                                   flatten = FALSE,
-                                   ...) {
-  effects <- match.arg(effects)
+find_parameters.merMod <- function(x, effects = "all", flatten = FALSE, ...) {
+  effects <- validate_argument(effects, c("all", "fixed", "random"))
 
   # installed
   check_if_installed("lme4")
@@ -207,21 +200,15 @@ find_parameters.rlmerMod <- find_parameters.merMod
 find_parameters.glmmadmb <- find_parameters.merMod
 
 #' @export
-find_parameters.merModList <- function(x,
-                                       effects = c("all", "fixed", "random"),
-                                       flatten = FALSE,
-                                       ...) {
-  effects <- match.arg(effects)
+find_parameters.merModList <- function(x, effects = "all", flatten = FALSE, ...) {
+  effects <- validate_argument(effects, c("all", "fixed", "random"))
   find_parameters(x[[1]], effects = effects, flatten = flatten, ...)
 }
 
 
 #' @export
-find_parameters.svy2lme <- function(x,
-                                    effects = c("all", "fixed", "random"),
-                                    flatten = FALSE,
-                                    ...) {
-  effects <- match.arg(effects)
+find_parameters.svy2lme <- function(x, effects = "all", flatten = FALSE, ...) {
+  effects <- validate_argument(effects, c("all", "fixed", "random"))
 
   # we extract random effects only when really necessary, to save
   # computational time. In particular model with large sample and
@@ -241,11 +228,8 @@ find_parameters.svy2lme <- function(x,
 
 
 #' @export
-find_parameters.HLfit <- function(x,
-                                  effects = c("all", "fixed", "random"),
-                                  flatten = FALSE,
-                                  ...) {
-  effects <- match.arg(effects)
+find_parameters.HLfit <- function(x, effects = "all", flatten = FALSE, ...) {
+  effects <- validate_argument(effects, c("all", "fixed", "random"))
 
   # installed
   check_if_installed("lme4")
@@ -269,16 +253,13 @@ find_parameters.HLfit <- function(x,
 
 
 #' @export
-find_parameters.sem <- function(x,
-                                effects = c("all", "fixed", "random"),
-                                flatten = FALSE,
-                                ...) {
+find_parameters.sem <- function(x, effects = "all", flatten = FALSE, ...) {
+  effects <- validate_argument(effects, c("all", "fixed", "random"))
+
   if (!.is_semLme(x)) {
     return(NULL)
   }
 
-  effects <- match.arg(effects)
-
   l <- compact_list(list(
     conditional = names(x$coef),
     random = colnames(x$ranef)
@@ -289,15 +270,11 @@ find_parameters.sem <- function(x,
 
 
 #' @export
-find_parameters.cpglmm <- function(x,
-                                   effects = c("all", "fixed", "random"),
-                                   flatten = FALSE,
-                                   ...) {
+find_parameters.cpglmm <- function(x, effects = "all", flatten = FALSE, ...) {
+  effects <- validate_argument(effects, c("all", "fixed", "random"))
   # installed
   check_if_installed("cplm")
 
-  effects <- match.arg(effects)
-
   # we extract random effects only when really necessary, to save
   # computational time. In particular model with large sample and
   # many random effects groups may take some time to return random effects
@@ -316,14 +293,10 @@ find_parameters.cpglmm <- function(x,
 
 
 #' @export
-find_parameters.coxme <- function(x,
-                                  effects = c("all", "fixed", "random"),
-                                  flatten = FALSE,
-                                  ...) {
+find_parameters.coxme <- function(x, effects = "all", flatten = FALSE, ...) {
+  effects <- validate_argument(effects, c("all", "fixed", "random"))
   check_if_installed("lme4")
 
-  effects <- match.arg(effects)
-
   if (effects == "fixed") {
     l <- list(conditional = names(lme4::fixef(x)))
   } else {
@@ -342,15 +315,11 @@ find_parameters.coxme <- function(x,
 
 
 #' @export
-find_parameters.mixed <- function(x,
-                                  effects = c("all", "fixed", "random"),
-                                  flatten = FALSE,
-                                  ...) {
+find_parameters.mixed <- function(x, effects = "all", flatten = FALSE, ...) {
+  effects <- validate_argument(effects, c("all", "fixed", "random"))
   # installed
   check_if_installed("lme4")
 
-  effects <- match.arg(effects)
-
   if (effects == "fixed") {
     l <- list(conditional = names(lme4::fixef(x$full_model)))
   } else {
@@ -365,14 +334,10 @@ find_parameters.mixed <- function(x,
 
 
 #' @export
-find_parameters.lme <- function(x,
-                                effects = c("all", "fixed", "random"),
-                                flatten = FALSE,
-                                ...) {
+find_parameters.lme <- function(x, effects = "all", flatten = FALSE, ...) {
+  effects <- validate_argument(effects, c("all", "fixed", "random"))
   check_if_installed("lme4")
 
-  effects <- match.arg(effects)
-
   if (effects == "fixed") {
     l <- list(conditional = names(lme4::fixef(x)))
   } else {
@@ -394,11 +359,9 @@ find_parameters.lme <- function(x,
 
 
 #' @export
-find_parameters.glmm <- function(x,
-                                 effects = c("all", "fixed", "random"),
-                                 flatten = FALSE,
-                                 ...) {
-  effects <- match.arg(effects)
+find_parameters.glmm <- function(x, effects = "all", flatten = FALSE, ...) {
+  effects <- validate_argument(effects, c("all", "fixed", "random"))
+
   s <- summary(x)
   fe_params <- rownames(s$coefmat)
   re_params <- rownames(s$nucoefmat)
@@ -413,16 +376,14 @@ find_parameters.glmm <- function(x,
 
 
 #' @export
-find_parameters.BBmm <- function(x,
-                                 effects = c("all", "fixed", "random"),
-                                 flatten = FALSE,
-                                 ...) {
+find_parameters.BBmm <- function(x, effects = "all", flatten = FALSE, ...) {
+  effects <- validate_argument(effects, c("all", "fixed", "random"))
+
   l <- compact_list(list(
     conditional = rownames(x$fixed.coef),
     random = x$namesRand
   ))
 
-  effects <- match.arg(effects)
   .filter_parameters(l,
     effects = effects,
     flatten = flatten,
@@ -432,16 +393,14 @@ find_parameters.BBmm <- function(x,
 
 
 #' @export
-find_parameters.glimML <- function(x,
-                                   effects = c("all", "fixed", "random"),
-                                   flatten = FALSE,
-                                   ...) {
+find_parameters.glimML <- function(x, effects = "all", flatten = FALSE, ...) {
+  effects <- validate_argument(effects, c("all", "fixed", "random"))
+
   l <- compact_list(list(
     conditional = names(x@fixed.param),
     random = names(x@random.param)
   ))
 
-  effects <- match.arg(effects)
   .filter_parameters(l,
     effects = effects,
     flatten = flatten,
diff --git a/man/find_parameters.glmmTMB.Rd b/man/find_parameters.glmmTMB.Rd
index 5e005d174..37fb4a0ad 100644
--- a/man/find_parameters.glmmTMB.Rd
+++ b/man/find_parameters.glmmTMB.Rd
@@ -2,21 +2,9 @@
 % Please edit documentation in R/find_parameters_mixed.R
 \name{find_parameters.glmmTMB}
 \alias{find_parameters.glmmTMB}
-\alias{find_parameters.hglm}
-\alias{find_parameters.merMod}
 \title{Find names of model parameters from mixed models}
 \usage{
 \method{find_parameters}{glmmTMB}(x, effects = "all", component = "all", flatten = FALSE, ...)
-
-\method{find_parameters}{hglm}(
-  x,
-  effects = c("all", "fixed", "random"),
-  component = c("all", "conditional", "dispersion"),
-  flatten = FALSE,
-  ...
-)
-
-\method{find_parameters}{merMod}(x, effects = c("all", "fixed", "random"), flatten = FALSE, ...)
 }
 \arguments{
 \item{x}{A fitted model.}