Right now I'm using two different bikes. A Trek 7.1fx as my main commuter and then a Mongoose(pre-Walmart) single-speed as my beater bike. however, the bottom bracket on the Mongoose is worn and the cranks have a slight wobble due to it. The rear wheel is also a bit out of true. Despite that, it still rides fine. So I'm wondering, would it be a good idea to get those things fixed? It would cost about $60. Since it's just a beater bike, would it be a good idea to invest money into? Or should I wait til it gets worse to a certain point? Any help would be appreciated. What would you do?