Indeed. Replace your batteries (or at least check on them) even if they still work (and if you have some valuable or special games you don't ever play, probably best to remove the battery and not replace it). And keep in mind that most of the time when a battery leaks, it's as a corrosive vapor and not necessarily the electrolyte fluid itself, so the cart can have corrosive fumes trapped inside it.

I have a DKC SNES cart whose battery leaked and corroded part of the board. Some of it got under the chips and it destroyed the MAD-1 chip, so the game is currently unplayable until I find a donor. I had to remove all the chips, clean them, clean the board, repair a trace, and bodge a repair to the MAD-1 (which was unsuccessful as the corrosion seems to have gotten inside the chip itself).