Oh, yeah. Obviously over time, but even if they're dirty from sweat buildup.
If they're dirty and you feel like you're losing control, you can put a death-grip on the club, which prevents you from allowing your wrists to hinge and unhinge naturally.
The general rule is to regrip every 6 months to year, but you can make them last a little longer by washing them with soap and warm water, then rubbing them with fine sandpaper.
If you don't have the cash to regrip them, I'd go with that. But since it's been two years, I'd recommend regripping them.