What does a broken drum bearing on a clothes dryer mean in terms of it's lifespan. Will it breakdown altogether anytime soon? Is it expensive to fix?

If you continue to use it it will probably fail soon. If you have a company that gives you an estamate, you could compare that to the price of a new dryer.

Markwilde - There are two bearings on thr tub ,one on front side and one on the back side, To replace these it is not a easy job, you have to replace the holders for the bearuings also , the cost doing iot yourself is not much for the parts ,about $ 75.00 I think , KISS GAVE YOU SOME GOOD ADVICE AND I WOULD CHECK INTO THAT FIRST . Go to a actuan and you could probably get one that is as good as the one you had or even maybe better . Im talking about at a home where they are selling every thing :: Good luck and GOD BLESS ::: F,B,E,