I will write this but I should first add the caveat that I work as a part-time mechanic/wheelbuilder at a bike shop so it's pretty easy for me to access all the tools I need whenever I need them.
I generally give my bike a good once-over every other week.
- lube the chain
- check the wear on the chain
- adjust the shifting
- true the wheels
- clean the whole bike
Probably once a month I pull the whole drivetrain off and give it a good cleaning, scrubbing the cassette and pulling the cranks off to get a better angle on cleaning the chainrings.
As for the BB, it's pretty easy depending on what you are running. You just need to get the BB tool appropriate for your BB. What are you running? Is it a newer Shimano two-piece crank with an external bearing? If so, it should be really easy. You just use a Shimano TL-FC16 crank arm tool and a 5mm hex key to loosen your non-drive crank, pull that crank off of the splined axle and pull the drive side crank through the BB shell then use a BB tool (I would recommend the Park BBT-9 because it has a TL-FC16 attached to it) to loosen the BB bearings. Just make sure to remember that, unlike your pedals, the drive side of your BB is reverse thread and your non-drive side is standard thread.
Also keep in mind that the torque specs on the BB is around 350 in/lbs
Good luck! :)
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