diff --git a/DESCRIPTION b/DESCRIPTION
index 616e7a5..0d52fcc 100644
--- a/DESCRIPTION
+++ b/DESCRIPTION
@@ -1,7 +1,7 @@
 Package: quantities
 Type: Package
 Title: Quantity Calculus for R Vectors
-Version: 0.2.1
+Version: 0.2.1.1
 Authors@R: c(
     person("Iñaki", "Ucar", email="iucar@fedoraproject.org",
       role=c("aut", "cph", "cre"), comment=c(ORCID="0000-0001-6403-5550")))
@@ -22,6 +22,6 @@ Suggests: dplyr (>= 1.0.0), vctrs (>= 0.5.0), tidyr, pillar, ggplot2 (> 3.2.1),
     testthat, vdiffr, knitr, rmarkdown
 LinkingTo: Rcpp (>= 0.12.10)
 ByteCompile: yes
-RoxygenNote: 7.2.2
+RoxygenNote: 7.2.3
 Roxygen: list(old_usage = TRUE)
 VignetteBuilder: knitr
diff --git a/NEWS.md b/NEWS.md
index 0f80deb..c73fd78 100644
--- a/NEWS.md
+++ b/NEWS.md
@@ -1,3 +1,7 @@
+# quantities devel
+
+- Performance improvements for `data.frame` methods.
+
 # quantities 0.2.1
 
 - Fix a couple of tests (r-quantities/units#324).
diff --git a/R/drop.R b/R/drop.R
index ee31ae9..5b2cdbf 100644
--- a/R/drop.R
+++ b/R/drop.R
@@ -30,9 +30,5 @@ drop_errors.quantities <- drop_units.quantities
 #' @name drop_quantities
 #' @export
 drop_quantities.data.frame <- function(x) {
-  for (i in seq_along(x)) {
-    if (inherits(x[[i]], "quantities"))
-      x[[i]] <- drop_quantities(x[[i]])
-  }
-  x
+  dfapply(x, function(i) if (inherits(i, "quantities")) drop_quantities(i) else i)
 }
diff --git a/R/misc.R b/R/misc.R
index f86d5aa..bfd3742 100644
--- a/R/misc.R
+++ b/R/misc.R
@@ -86,18 +86,8 @@ diff.quantities <- function(x, lag = 1L, differences = 1L, ...) reclass(NextMeth
 #' as.data.frame(z)
 #'
 #' @export
-as.data.frame.quantities <- function(x, row.names = NULL, optional = FALSE, ...) {
-  e <- errors(x)
-  dim(e) <- dim(x)
-  e <- as.data.frame(e)
-  value <- NextMethod()
-  if (!optional && ncol(value) == 1)
-    colnames(value) <- deparse(substitute(x))
-  for (i in seq_len(ncol(value))) {
-    value[[i]] <- reclass(value[[i]])
-    errors(value[[i]]) <- e[[i]]
-  }
-  value
+as.data.frame.quantities <- function(x, ...) {
+  dfapply(as.data.frame(drop_units(x), ...), as_units, units(x))
 }
 
 #' Coerce to a List
diff --git a/R/utils.R b/R/utils.R
index ca51a84..1c43f44 100644
--- a/R/utils.R
+++ b/R/utils.R
@@ -3,3 +3,10 @@ reclass <- function(x) {
     class(x) <- c("quantities", "units", "errors")
   x
 }
+
+dfapply <- function(X, FUN, ...) {
+  attrs <- attributes(X)
+  X <- lapply(X, FUN, ...)
+  attributes(X) <- attrs
+  X
+}
diff --git a/man/as.data.frame.quantities.Rd b/man/as.data.frame.quantities.Rd
index dc33c8d..db9ab52 100644
--- a/man/as.data.frame.quantities.Rd
+++ b/man/as.data.frame.quantities.Rd
@@ -4,23 +4,11 @@
 \alias{as.data.frame.quantities}
 \title{Coerce to a Data Frame}
 \usage{
-\method{as.data.frame}{quantities}(x, row.names = NULL, optional = FALSE,
-  ...)
+\method{as.data.frame}{quantities}(x, ...)
 }
 \arguments{
 \item{x}{any \R object.}
 
-\item{row.names}{\code{NULL} or a character vector giving the row
-    names for the data frame.  Missing values are not allowed.}
-
-\item{optional}{logical. If \code{TRUE}, setting row names and
-    converting column names (to syntactic names: see
-    \code{\link[base]{make.names}}) is optional.  Note that all of \R's
-    \pkg{base} package \code{as.data.frame()} methods use
-    \code{optional} only for column names treatment, basically with the
-    meaning of \code{\link[base]{data.frame}(*, check.names = !optional)}.
-    See also the \code{make.names} argument of the \code{matrix} method.}
-
 \item{...}{additional arguments to be passed to or from methods.}
 }
 \description{
diff --git a/man/cbind.quantities.Rd b/man/cbind.quantities.Rd
index e39a9a6..9f0652e 100644
--- a/man/cbind.quantities.Rd
+++ b/man/cbind.quantities.Rd
@@ -19,8 +19,9 @@
 
 \item{deparse.level}{integer controlling the construction of labels in
     the case of non-matrix-like arguments (for the default method):\cr
-    \code{deparse.level = 0} constructs no labels; the default,\cr
-    \code{deparse.level = 1 or 2} constructs labels from the argument
+    \code{deparse.level = 0} constructs no labels;\cr
+    the default \code{deparse.level = 1} typically and
+    \code{deparse.level = 2} always construct labels from the argument
     names, see the \sQuote{Value} section below.}
 }
 \description{