With hands that have two pair in the hole (KK33, TT55, etc) that are just looking for sets, what is a general guideline? Is KK33 better than, say, TT88? Is 4477 too low to play? Is there an (approximate) general rule for minimum size?

Thanks,
OD

There's no rule for what hands to play preflop. What you've got to be looking at when considering to play a hand is stacksizes, opponents and relative position. I would avoid playing low double paired hands, especially when very deep as the value of bottom set goes down as stacksize increases. I think doublepaired hands are very good to mix up and 3beta tonne. They play very well fit or fold postflop and we are going to have the initiative and win the pot on hi card flops alot + have deception when we do hit a set. also good for balance to have sets in our 3b range on boards that typically miss the hands we're 3betting. as stacks get shorter the value of KK33 type hands goes up since overpair value is more relevant. Also should be considering connectivity/suits when deciding whether to play a hand, 7788ds plays alot better than qq77r.

100bbs I'm playing the majority of my double paired hands simply cos they're so easy to play and I'm happy stacking off whenever I hit a set. Deeper the more speculative ones lose alot of value and I'd avoid playing.

pairs below 7 are not worth seeing a flop most of the time as you can rarely be sure they are the best set even when they hit, connected low pairs like 5543 with a suit are more playable but are still trouble hands, especially deep - a lot of players better than me don't even play them

4477 is trashy because the 44 is practically worthless and the 74 does not work very well together, even on a 56 flop its

kk33 and 101088 are both very playable although stacks are always an issue, the kk can become pretty marginal deep and/or OOP because the 33 is so weak

I have learned the hard way that 2 low pairs cost people alot of money!

As Olangatang has already said, there are no hard rules on what 2pair hands to play and stacksizes, opponents, relative position and any action already in the hand will all affect how you should play these hands. Dont be afraid to open and 3bet alot in position with mid -> High 2 pairs (88TT, KK99, QQ77 etc) and likewise dont get attached to low 2-pairs or uncordinated pairs (3355, JJ22 etc) when facing action