wheel bearings

[glide]

How long should wheel bearings last between replacements?
I had all four wheel bearings replaced shortly after I purchased the car in 1999, around 66,000 miles on it.

I now have around 120K miles on it, and I am starting to hear the rumblings again. The car is not a daily driver so I am no hurry to get it done, but it feels like I just had them replaced.

Is this an average amount of time between replacements, or is this a sign that my suspension should be looked at as well?