How long are shocks good for?

I drive an 01 Ford Sport Trac that currently has 210k miles. I got the truck 4 years ago with about 120k miles on it. Within a year of having the vehicle the shocks were replaced. A couple of days ago I noticed the front drivers side was squeaking quite loud. I pulled the skirt from behind the tire and looked at the control arm bushings. (Upper) they seem to be worn out and I'm sure they're factory bushings. I've lubricated them but the squeaking persists. I'm beginning to wonder if it is the shock? How long are they good for and is there anything I can do to top it temporarily? I leave for basic training in January and I'm just trying to get by until I have the money to fix it myself.

Check the bolts and hinges around the wheel well. A few years ago my 5 year old CPO car had a squeak. Only 40,000 miles. Turns out it was just a dry bolt that was rusty.

Struts, atleast quality ones, should last as long as the OE ones are. It also depends on what driving conditions you put them under. If you drive through bumps terrain or haul heavy weight, it would wear down the struts quicker.

I would try to push on the suspension and having someone looking for the squeak after you drive around for a few days. Sometimes condensation builds up and puts some surface rust on the struts.