If your normal small raise would be more than 1/4-1/3 of the effective stack depth, it is often right to push instead.
Open-pushing for 10 bb to attack a pot of 1.5 bb is not that different from pushing for 15 bb after a couple of players limp to make the pot 3.5 bb. The amount you risk is actually smaller in relation with the reward. Sometimes it can be right to push an even wider range after limpers, but be careful that some bad players like to limp/call with mediocre hands like QTs, 33, and A5o, so try not to push hands that do too badly against hands like these if your read is that you may get a crazy call.
After several limps, it is reasonable to push for much more than 15 bb. You should be inclined to push larger amounts if you are in the blinds, so that playing a multiway pot out of position is not a great option.
If there is a short stack who will get good odds to call, this reduces the amount of dead money in the pot, which means you should not push quite as widely even if you expect to be ahead of the short stack's range.