My parts are all going to be here soon to service my front and rear wheels, and I ordered enough spare ball bearings to service the bottom bracket, as well.

(My lbs is a bit of a drive away, so it's more convenient, and cheaper, to just order parts)

My question is:

Would I be wise to service the existing cup and cone bottom bracket on this 87 Schwinn Traveler, or should I replace it with a cartridge style?

Fwiw, the bb shell looks to be 68mm wide. (Checked with my calipers)

I know it's cheaper to just service the bearings and such, but is it worthwhile in the long run to replace with a cassette and a new crank? or would I be getting into a lot of extra expense that I don't need right now. (I plan to eventually upgrade the gearing, derailers, shifters, and crank and such, but that is a ways down the road, as I am happy with the bike as is right now...with some much needed wheel and bb maintenance)

Relative noob here, so that's why so many questions.

Thanks for any help!