pedestrian cyclistBB-UN300 held up around 18 months on my commuter. Changing it is a little annoying, but is it really worth the effort going for a more premium part if a spare costs just 12€?
Practically speaking, premium square tapered BBs go fo 100-200€, and I don't think they will last 20-30 years... And then there's the risk of theft that someone has to be factored in.