Re: Maintenance nightmare
I've not yet had to deal with actual Intel NUCs yet, but have dealt with a number of other well known brands of the same form factor. The most common repair is replacing the fan, on all brands and models I've seen, either because it's noisy or has failed completely. I don't think I ever repaired one by simply cleaning it because that has never actually worked. On the other hand, replacing the fan is pretty simple, if not especially cheap since you need that precise model of fan from the OEM. NUCs may be different if it's as difficult to replace as you say.