Get your battery load tested by a reputable shop. Auto parts stores can also do this for free, or nearly nothing. Then, assuming you have no other electrical system faults, such as something that is slowly draining the battery, or a dying starter, you might be wise to go ahead and replace the battery.
Remember that heat, cold and time are the enemies of automotive batteries. If you wait until your battery dies, decide what the trade-offs in convenience and cost are. If you’re OK with having it fail at an unpredictable time, then go ahead – roll the dice. ~ Bill