Here's my problem, and it's heads up related, more specifically 25bb cap heads up -

When players limp on the small blind(button), I rarely raise preflop as I've came to the conclusion that checking back is more profitable.

However, since my iso raise percentage is so low, I feel that players can literally limp any 2 cards profitably against me.

So to to put it another way -

I assume checking back has a higher EV for me, but at the same time it allows my opponent to profitably limp any 2 cards.

It sounds "wrong" to me that my opponent should be able to profitabley limp with any 2 cards, however I don't won't to take what I assume is a lower EV line (raising), just to stop him from limping any 2 cards. As I find checking back to be higher EV.

Would appreciate if someone can help me with my thought process here, thanks.

I raise pretty wide as default readless in this spot. Typically my opponents are very weak when they limp and if they're strong then they'll usually reraise me. So once they limp and call my raise I'm pretty confident in having a decent ev edge there.

At the risk of people exploiting me, here's my big blind raising range vs an unknown button limper 25bb deep for a 4xbb raise, which makes for an 8bb pot with 21bb behind:

66+, A9s+, ATo+, KTs+, KJo+, QTs+, QJo, J9s+, T9s.

Then with reads that they limp and fold a lot, I'll add lots of suited connectors. With the opposite read that they limp and call a lot, I'll check QJo, JTs, J9s, T9s, but I'll add hands to my raising range such as 55, A8s, A9o, K9s.

I would limp a lot vs you if your raising range is extra tight.

Your default iso range is very tight too, it's only like 15% of hands, right?

That's about the same as mine. Which is actually very low compared to the standard iso %'s in these games.

Are you shoving hands like low aces, etc? I mean what's your combined non all in and all in raise percentage?

As stacks get deeper I'll add more hands because I'm threatening more reverse implied odds and have more postflop bluffing opportunities. With only 25 bb I think you're fine if you're raising a similar range.

How much do you raise to as default?

3x, I see you raise to 4x, and I have mixed opinions on it.

Why do you go for 4x?

Because 3x gets called too much in my experience. 4x gets a good mix of folds and calls. I'm getting the action I want from bad hands and am getting a good amount of folds when I have suited connectors.

That, and 5x just gets too many folds for my liking. I've tried many different sizes in this spot and have settled on 4x for my default raise size.

However, I see nothing inherently wrong about raising 3x, except to say that you should definitely be raising slightly wider than the range I listed specifically because of the size of your investment relative to the pot.

On the other hand if you wanna go up to 5x I think you should play somewhat tighter.

just raise bigger untill he stops limping. if he starts limpraising, minraise his limps and cbet. or donk into him a lot if his limping range is capped, or if he is bluffing a lot when you arent raising and fold to your raises, try not raising strong hands and trap him. just balance your ranges in every spot where he might bluff and put pressure on him in spot where he folds too much