You probably just want to use mod_expires, as this allow for sending of both Cache-Control header and Expires headers automatically and can allow you to specify by both access time and file modification time. It also allows you to set different defaults by file type.
Using mod_expires you could set the default expiry using the following directive:
ExpiresDefault "access plus 2 days"
Of course mod_headers is a much more general module that allows you to do some of the same stuff, but generally used more for creating custom headers or manage multiple (possibly conflicting) headers.
原文：http://stackoverflow.com/questions/12164684/mod-expires-or-mod-headers
2：一个比较全的对这个两个cache方式的配置文件。
# ##############################################################################
# # MEDIA TYPES AND CHARACTER ENCODINGS #
# ##############################################################################
# ------------------------------------------------------------------------------
# | Media types |
# ------------------------------------------------------------------------------
# Serve resources with the proper media types (formerly known as MIME types).
# http://www.iana.org/assignments/media-types/media-types.xhtml
<IfModule mod_mime.c>
# Audio
AddType audio/mp4 f4a f4b m4a
AddType audio/ogg oga ogg opus
# Data interchange
AddType application/json json map topojson
AddType application/ld+json jsonld
AddType application/vnd.geo+json geojson
# JavaScript
# Normalize to standard type.
# http://tools.ietf.org/html/rfc4329#section-7.2
AddType application/javascript js
# Manifest files
# If you are providing a web application manifest file (see the
# specification: http://w3c.github.io/manifest/), it is recommended
# that you serve it with the `application/manifest+json` media type.
#
# Because the web application manifest file doesn't have its own
# unique file extension, you can set its media type either by matching:
#
# 1) the exact location of the file (this can be done using a directive
# such as `<Location>`, but it will NOT work in the `.htaccess` file,
# so you will have to do it in the main server configuration file or
# inside of a `<VirtualHost>` container)
#
# e.g.:
#
# <Location "/.well-known/manifest.json">
# AddType application/manifest+json json
# </Location>
#
# 2) the filename (this can be problematic as you will need to ensure
# that you don't have any other file with the same name as the one
# you gave to your web application manifest file)
#
# e.g.:
#
# <Files "manifest.json">
# AddType application/manifest+json json
# </Files>
AddType application/x-web-app-manifest+json webapp
AddType text/cache-manifest appcache manifest
# Video
AddType video/mp4 f4v f4p m4v mp4
AddType video/ogg ogv
AddType video/webm webm
AddType video/x-flv flv
# Web fonts
AddType application/font-woff woff
AddType application/font-woff2 woff2
AddType application/vnd.ms-fontobject eot
# Browsers usually ignore the font media types and simply sniff
# the bytes to figure out the font type.
# http://mimesniff.spec.whatwg.org/#matching-a-font-type-pattern
# Chrome however, shows a warning if any other media types are used
# for the following two font types.
AddType application/x-font-ttf ttc ttf
AddType font/opentype otf
AddType image/svg+xml svg svgz
# Other
AddType application/octet-stream safariextz
AddType application/x-chrome-extension crx
AddType application/x-opera-extension oex
AddType application/x-xpinstall xpi
AddType application/xml atom rdf rss xml
AddType image/webp webp
AddType image/x-icon cur ico
AddType text/vtt vtt
AddType text/x-component htc
AddType text/x-vcard vcf
</IfModule>
# ------------------------------------------------------------------------------
# | Reducing MIME type security risks |
# ------------------------------------------------------------------------------
# Prevent some browsers from MIME-sniffing the response.
# This reduces exposure to drive-by download attacks and cross-origin data
# leaks, and should be left uncommented, especially if the web server is
# serving user-uploaded content or content that could potentially be treated
# as executable by the browser.
# http://www.slideshare.net/hasegawayosuke/owasp-hasegawa
# http://blogs.msdn.com/b/ie/archive/2008/07/02/ie8-security-part-v-comprehensive-protection.aspx
# http://msdn.microsoft.com/en-us/library/ie/gg622941.aspx
# http://mimesniff.spec.whatwg.org/
<IfModule mod_headers.c>
Header set X-Content-Type-Options "nosniff"
</IfModule>
# ------------------------------------------------------------------------------
# | ETags |
# ------------------------------------------------------------------------------
# Remove `ETags` as resources are sent with far-future expires headers.
# https://developer.yahoo.com/performance/rules.html#etags
# `FileETag None` doesn't work in all cases.
<IfModule mod_headers.c>
Header unset ETag
</IfModule>
FileETag None
# ------------------------------------------------------------------------------
# | Expires headers |
# ------------------------------------------------------------------------------
# Serve resources with far-future expires headers.
# IMPORTANT: If you don't control versioning with filename-based cache
# busting, consider lowering the cache times to something like one week.
<IfModule mod_expires.c>
ExpiresActive on
ExpiresDefault "access plus 1 month"
# CSS
ExpiresByType text/css "access plus 1 year"
# Data interchange
ExpiresByType application/json "access plus 0 seconds"
ExpiresByType application/ld+json "access plus 0 seconds"
ExpiresByType application/vnd.geo+json "access plus 0 seconds"
ExpiresByType application/xml "access plus 0 seconds"
ExpiresByType text/xml "access plus 0 seconds"
# Favicon (cannot be renamed!) and cursor images
ExpiresByType image/x-icon "access plus 1 week"
# HTML components (HTCs)
ExpiresByType text/x-component "access plus 1 month"
# HTML
ExpiresByType text/html "access plus 0 seconds"
# JavaScript
ExpiresByType application/javascript "access plus 1 year"
# Manifest files
ExpiresByType application/manifest+json "access plus 1 year"
ExpiresByType application/x-web-app-manifest+json "access plus 0 seconds"
ExpiresByType text/cache-manifest "access plus 0 seconds"
# Media
ExpiresByType audio/ogg "access plus 1 month"
ExpiresByType image/gif "access plus 1 month"
ExpiresByType image/jpeg "access plus 1 month"
ExpiresByType image/png "access plus 1 month"
ExpiresByType video/mp4 "access plus 1 month"
ExpiresByType video/ogg "access plus 1 month"
ExpiresByType video/webm "access plus 1 month"
# Web feeds
ExpiresByType application/atom+xml "access plus 1 hour"
ExpiresByType application/rss+xml "access plus 1 hour"
# Web fonts
ExpiresByType application/font-woff "access plus 1 month"
ExpiresByType application/font-woff2 "access plus 1 month"
ExpiresByType application/vnd.ms-fontobject "access plus 1 month"
ExpiresByType application/x-font-ttf "access plus 1 month"
ExpiresByType font/opentype "access plus 1 month"
ExpiresByType image/svg+xml "access plus 1 month"
</IfModule>
摘选自： http://stackoverflow.com/questions/9933012/how-to-use-mod-headers-and-mod-expires-to-cache
相关资料： http://www.askapache.com/htaccess/apache-speed-compression.html