True...

If a DIGITAL camera is over five years old, replacing the shutter may not make any sense at all. It may be wiser to buy a newer model. Where I worked, we used hundreds of mid-range Canons (EOS 5D, 7D, 10D, 20D, 30D, 40D, and 50D). After five years, we would usually replace any camera that failed. It was worth it to have newer technology.

When we were budgeting to replace several hundred long-roll portrait cameras (Camerz ZII and ZIII models), we considered buying heavy duty Canons. Then we realized that we could by three or four mid-range bodies for the cost of one top-end Canon. We also realized that the top end model would not make a better portrait than the midrange model. Then we realized that the "pro" model would last so long that it would be obsolete well before it died. Heck, as it was, we replaced a few repairable 20D and 30D Canons with 40D and 50D models.

At some point, manufacturers stop making parts for older bodies, so repairs become difficult or impossible. At the same time, the newer cameras have features we're already drooling over. So personally, if a five-year old camera costs more than $250 to repair, I'll consider replacing it. If it has reached its estimated MTBF (mean time before failure) rating, I WILL replace it. If it reaches 7 years old, I WILL replace it.

It's not 1973 any more... Most cameras are not meant to be used for more than a few years.