If i use a deep cycle as just a starting battery, do i have to recharge it?

So i have another question on here but i didnt get to ask this one. If i do buy the deep cycle battery, for my 18 ft bowrider 90 hp force outboard, do i have to recharge it? Im reading that you have to recharge them after discharge but will mine be discharged because i dont have a trolling motor or electronics. Can i litterally just buy the deep cycle battery and put it in my boat and be good for the summer?