The fabric attachment system is low-tech, but that seems to be helpful, as it can adapt to seat rails of different widths. One fancier option you might see on more expensive seat bags is a quick-release mount that you install under your saddle. But those have a fixed width, and therefore can fit under seats with only those exact specs. Brooks saddles, for example, are too wide for these mounts.
Over the years, I’ve come across plenty of articles that claim to tell you how to build up your cycling toolkit for cheap. Somehow the word “cheap” stops recurring in the long list of “essential” bike repair bits and pieces. The truth is, there is no real way to build a whole shop of tools all at once without plopping down a few hundred bucks. But in an attempt to show everyone that not all of us truly need a full complement of bike tools, I present the truest, most budget-conscious, and barest of bones options to you.
Modern bottom brackets use a sealed bearing type construction that keeps water and debris locked out, so they seldom go wrong. Maintenance is impossible so they need replacing when they do wear out. Older style cup bottom brackets need to be re-greased every now and again, and occasionally will need to have their bearings replaced. There are a lot more teeth on the chainring cogs than those on the rear cassette, so need changing less regularly. Cranks usually a solid one piece construction so there is not much to go wrong.