100,000 miles on bettle. When my wife warms it up in the morning the battery goes dead and it dies. Under normal use it is fine. Just problemic when long idle times, 8 minutes or so.
What is the alternater life?
It is anyone's guess; I would have the whole charging system checked and determine what is wrong (most auto parts store will hook up a diagnostic computer for free). Typically, in alternators two things wear out; bearings and regulator/brushes and sometimes other internal components. In the Bosch versions, the brushes/regulator can be purchased separately and replaced (saving the cost of a whole alternator); of course, since you are doing all the work and you have 100k, I would just get a high quality rebuild (if thats what your problem is). If you buy a new brush/regulator part; then, the bearings wear out, your back to square one and have to replace the whole thing anyway. DO NOT buy cheap rebuilt alternators from your typical auto parts stores; get a oem rebuild or new, there is a difference and you will be rewarded with reliability and a long life component. Do the job once and do it right with quality oem parts.
Check out Bosch's website for your application (usually our cars come with Bosch, Valeo, Hitachi oem alternators: check yours to be sure etc.):