Electrical – I am a cleaner. I apparently got water into an external powerpoint

It's more likely that the problem you're experiencing is high inrush current. All the gear you have connected is going to use switchmode power supplies, which have characteristic high inrush current when first connected to power as large capacitors inside charge. The inrush current for a switchmode supply can be many times higher than its normal consumption, though only for a very short period (less than a second). See the inrush current row of this table.

It is possible that the combined inrush is enough to damage your board/pop fuses. The only way around this would be a board that can handle more current (may not be practical/easy to find one), or to stagger-start the devices - that, is don't have them all energise at once. Neither of these solutions is ideal, you may need to look at spreading the devices over two boards.

Breakers do wear out, and do fail, but without looking it up i would say that wear is not an issue until hundreds or thousands of trips. When they fail, they almost always fail open anyway. I have seen dozens of failed breakers, and they always fail open. Each breaker is tested several times at the factory, and one that has tripped few times in the field is probably more reliable since this type of device has higher failure rate at the beginning and end of life, with most reliable service after some use. Lifetime is not determined just by number of trips, but by how hot it gets for extended periods and, of course, it is working hardest just before it trips so if the circuit is overloaded but rarely trips the breaker is working harder than one that trips regularly due to short overloads.The former sounds like your situation so i would replace just to avoid nuisance trips in the future. Breakers are cheap.

Also, very old breakers have less stringent standards than new ones, depending on national electrical codes so for very old breakers it is always a good idea to upgrade when doing a major rewire.

Finally, when breakers do start to fail they often start to become too sensitive and trip at lower than rated current so if it trips a few times even though it looks like circuit is not overloaded its a good idea to change the breaker.