Owning a bicycle is a good idea, but taking care of it yearns for an experts’ piece of mind. You should not worry too much about taking your bicycle to a mechanic when you can handle the repairing on your own. It will rather save you the cost of every moment you get into a problem. Grab a pick of one of the toolkits from the above review. I assure you that, absolutely no day will you seek a mechanic for service.
These folks took me in right away, diagnosed and fixed my stripped handle bar clamps and had me on my way to work in about 15 minutes. Friendly, straightforward, understands the rider's objectives (in my case, how do I get home from work). Not to mention, the fee was reasonable. I have been in many bike repair places in my 6 decades. This is the best.
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.