Speed up zsh compinit by only checking cache once a day.

compinit-oh-my-zsh.zsh

# compinit optimization for oh-my-zsh
# On slow systems, checking the cached .zcompdump file to see if it must be 
# regenerated adds a noticable delay to zsh startup.  This little hack restricts 
# it to once a day.  It should be pasted into your own completion file.
#
# The globbing is a little complicated here:
# - '#q' is an explicit glob qualifier that makes globbing work within zsh's [[ ]] construct.
# - 'N' makes the glob pattern evaluate to nothing when it doesn't match (rather than throw a globbing error)
# - '.' matches "regular files"
# - 'mh+24' matches files (or directories or whatever) that are older than 24 hours.

#autoload -U compaudit compinit
#: ${ZSH_DISABLE_COMPFIX:=true}
# ...
setopt extendedglob
if [[ $ZSH_DISABLE_COMPFIX != true ]]; then
  # If completion insecurities exist, warn the user without enabling completions.
  if ! compaudit &>/dev/null; then
    # This function resides in the "lib/compfix.zsh" script sourced above.
    handle_completion_insecurities
  # Else, enable and cache completions to the desired file.
  else
    if [[ -n "${ZSH_COMPDUMP}"(#qN.mh+24) ]]; then
      compinit -d "${ZSH_COMPDUMP}"
      compdump
    else
      compinit -C
    fi
  fi
else
  if [[ -n "${ZSH_COMPDUMP}"(#qN.mh+24) ]]; then
    compinit -i -d "${ZSH_COMPDUMP}"
    compdump
  else
    compinit -C
  fi
fi