Considering the amount of time I spent riding, which I don't think has been all THAT much (however, there is a tremendous amount of uphill I do for strength training), is this considered kind of low/average/high for the life span of an octalink BB?

The only reason I haven't jumped the gun and grabbed one is I don't have the tool for it. I'm a hard working poor guy like many others around here so just being kind of a rookie in the biking scene, I have to often associate tools cost with the part cost for whatever upgrades I want to do.

I checked bikepedia to see if my shell was 68 or 73... it didn't have anything listed. Is there any kind of resource I can find to ultimately say "YES, this is 73mm" or whatever?