Things detoriate when they are not in use. Things detoriate while they are in use as well, but in a more controlled way - one gets to see the problems as they develop and can act on them, fix things ... while on things that aren't in use, all the problems comes suddenly as a big surprise. I do remember we had a period when the dhingy was not used much at all. The steering mechanism got rusty and stopped working at all, navigation lights didn't work, engine wouldn't start ... it was really a mess. It's still a mess, leaking really a lot now (even if I'm doing a best effort on patching it up) and has other problems as well ... but at least I'm aware of the problems, and it's still useful for me.
We've been doing summer vacations in Denmark all last years, and indeed ... we don't use the dhingy much there. With the current dhingy it's at least possible to use it in Copenhagen, without the engine (or with a low-powered engine) we never bothered taking the dhingy from the harbour we've been staying at and into Copenhagen.
Well, but things are stable,
the Evinrude engine I have was laying around for about 10 years in a barn. By coincidence I was sitting there, telling that I need a small outboard, but that they are very expensive. So my friend said: I have one, not used for 10 years, want it?
So I took it and noticed that one ignition spark is not working. I dismantled the whole engine and found the issue. After it did start and run I organized a new impeller, which was quite a challange for this old thing. That were the 50€ I had to spend on this thing.
The Evinrude is awesome. Such a small engine with 2 Cylinders and 4 HP. It's so light, I even could use it on my old dinghy, which was an Intex with a flexible mount