In .htaccess file, webmaster can give an advice to website visitors web browser to cache some kind of files for certain period of time.

there i want to ask if i can safelly cache .php files in visitors web browser cache? Is it good idea to decrease load or data transfer?

# static files cache 0.5 minute
<FilesMatch ".(php|html|htm)$">
Header set Cache-Control "max-age=30, private, proxy-revalidate"
some people advice using Memcached module to reduce mysql usage (storing frequently accessed data in ram) OR fastcgi_cache in ngx_http_fastcgi_module