I have trouble playing double pairs like 8822ss/r or 4422ss/r

trying to understand the strength of these hands.

I do see some players play then passively whereas some goes crazy with them.

Please share your style

pretty passive, but I'm willing to set mine. I don't want to build huge pots preflop ever because raw equity isn't good into overpairs, but flops are usually fairly easy to play (assuming you're comfortable w/ middle or bottom set.) I think the value of the highest pair matters a fair amount, like 88 still can hit top/middle set, 44 is basically all bottom set. Live games, I have more of a limping range, so I'm fine limping these types of hands, flatting opens, calling 3! with the "better" ones.

Also I think a big part is how many blockers you bluff, 88 is more like to block a board that interacts somewhat, and is more believable (ppl generally have more like 78 straights than 23, so blocker bluffing 22 is risky)

Stack sizes - who do you have position on, who has position on you, do you have enough room to potentially use your pair as blockers, are you going to be thinking about getting away from your bottom or middle set on certain boards with certain runouts
These hands don't want to get all-in so you want to minimise the chances of that by being less likely to call if you've got a bunch of people to act behind you and maximise your calling frequencies when you're closing the action. A raggedy double pair hand is good in the sense of you get instant feedback on the flop whether you've got a good enough hand to go with. Easy to play, not likely to make a big mistake.
Reads - implied odds, or the ability to make opponents' fold when you have a range advantage, i.e. them c-betting small or c/fing on a 578r board and they've 3b pf
You can 3b them pre a chunk and then auto-stack off if you hit one ~100bb deep if you like
You can call a single 3b with them a lot of the time
But you should also be folding them a bunch when they have no straight connectedness at all, especially from early position and especially when they're not like at least flushing as well.

Sort of a low playability factor as even when you do flop a set its usually bottom or middle set, and if they're DS you're always worried about a higher FD. Think they do better multiway then HU as you can dump them quickly if you don't flop 2pr+ - HU you'll find yourself having to bluff multi streets a lot given the perceived range advantage and no actual hand.

Playing mostly in position vs weak regs/fish and face up hands. Play sets fast and give them up when you’re getting raised in a spot only a bigger set makes sense in. Rarely 3bet them unless they are connected/suited. Ie: 6h6d7h7d

Maybe this is my 5c background speaking but I generally consider these small PPs trash hands. Probably starting to play them when we get to 7788+ since those can flop stronger sets that make the nuts on the flop enough of the time, but anything smaller is setting you up for serious reverse implied odds situations too often to make them worthwhile in my book.

"I'm for 'em!"

-Mitch Hedberg

Don't really like them if I can't make/block a straight with both cards. As others have said .. pot control and watch out for set v set spots that really sting your stack. GL