I'm going to take a guess and say you are new to this boating thing. When I first started going out in my new to me boat my only experience boating was running tinnies that you could smash into the dock or run WOT onto the beach. Man what a steep learning curve. I didn't even know how to use or put a fender on. Tie a bow line? are you kidding me. I would start stressing about launching the night before then as soon as we got out stress about breaking down which I did but actually didn't the first time. I couldn't start the boat, no crank, nada. So a kind man towed me in 4 miles. Took it to the marina and all it was is I didn't have the shifter centred, stuff like that. No bilge, I didn't connect the cable to the battery in the spring. Forgot to take of the straps so the boat wouldn't float off the trailer. Tripped the kill switch, freaked out, ask for a tow and the experienced boater asked about the kill switch, duh!. The stuff they don't teach to get your Boating Card here in Canada. Stuff like that? But that doesn't really answer your question. Of course it's going to break down but not from lack of maintenance or contingency, that I have learned. I put on a 15 HP kicker to troll, I really put it on to have a good backup, my 100 lb thrust hood ornament is now back up #2. My booster pack helps my battery stress level. Relax this boating is supposed to be relaxing, especially if you don't own one.
Experience is a lifetime of mistakes, wisdom is knowing how not to make them again.
You will be fine.
