I have an Allen Firearms/Uberti Old Model SAA, I bought in 1984 and did a complete action job on as soon as I got home with it, and to this day not showing any signs of bolt wear. I have shot Lord only knows how many rounds through it.
If it has not had an action job, and the gun is heavily used, I'd say you'd start seeing problems within a year or two, from my experiances.
RRio