Do you expect a fridge to work in six years?

Yes, I expect household appliances to last at least a decade. My current fridge is from 2004, and whilst it will probably need replacing soon, 20 years is not an unreasonable run.

Honestly, it depends on what you spend. Many high-end fridges in Europe come with 10 year manufacturer's warrantee. And EU law requires manufacturers to provide parts for 10 years on such goods. So honestly yeah.

That said, cheaper ones tend to make it past 5 (mine is 8 years old) without maintenance. And if I had to replace it 3 times in 10 years, it would still be cheaper than getting the expensive ones. (worse for the environment)

As for solar panels. I am about to replace the one on my boat. It is well over 5 years old and still works. I'm replacing it because I can get 2 410w huge panels for way less than the 100w one cost the past boat owner.

6 years really is nothing for a solar panel. My new ones came with a 20-year warrantee. (something like 85% after 20 year). High-end ones are better.

The 2 MPPTs are likely to need replacing first. But again, 6 years may be well beyond their warrantee. But is reasonable to expect. The lifepo4 battery should just manage 10 years. Before losing significant storage. But that is with the BMS set to keep them from 10-90% charge.

So no, 6 years is a very reasonable time to expect from solar.

EDIT: In a house setup. It is the inverter that is most likely to need replacing. But again, 6 years is more than likely for a quality one.

On my boat, the vast majority of the equipment is 12v, as it's just more efficient. But the cheap (very) Chinese inverter did not last a year. So yeah they can be cheap crap if you don't get good ones. But we don't really use it much. So haven't bother replacing it yet. Will do so this summer.