On our boat there is always something to spend money on, I guess also on all other boats. One time we got our engine room filled up with sea( the engine was only a few months old) so we had to change batteries( we have 4) all electricity, and engine starter and the two dynamos. But our incurance payed the most of it.
The alarm wasn't working, so we didn't find out before we saw that the boat was losing speed, so my father had to go and see and then he saw it. This happend also one time later, but at that time all systems were working, so we didn't get any damage.