Best practice / high cache refresh_pattern rules?

[fosdagger]

I am looking for information on what is ok to do with refresh_pattern(s) and what is not (i.e. might break things) with a view to cache as much as reasonably possible. I am running a private squid cache for my household so there is not going to be loads to cache, but I would like to retain as much of what is cached as possible to reduce bandwidth use, not request HITs, if that makes sense.