Dryers typically have double the service-life of washers, if not longer. My parents dryer is 19 years old and has had only one service incident, replacement of a thermostat. A friend gave a 35-years-old Kenmore dryer to me a couple years ago that they were going to toss out. It was "slow" so they thought the heating element was going bad (elements typically either work or not, they don't wear out and get cooler). I found the airflow was obstructed due to being clogged with lint (the handle on the filter was broken). I replaced the filter and rear drum seal that had a small tear, cleaned it up and sold it for $80.

Replacement of the motor requires full disassembly but is not a difficult job ... notwithstanding pulling down your stacked unit, which will likely add some labor cost for a servicer to do it.

You can look up the model number at SearsPartsDirect.com to check what's the ballpark price of the motor, with the understanding that price doesn't reflect what a servicer will charge (there are numerous online parts sources, Sears may or may not have the lowest price for a DIYer).

The serial numbers are coded for the year and week of manufacture. Answer back here with the serials if you'd like to know that info.

Thanks for the helpful reply. I had kind of thought the same about dryer life but I only got 9 years out of my GE junk that preceded this one so I was thinking that they just don't make them like they used to. Witness four thermistors and a handle so far.

Anyway, here's the info:
Model # 110.92822101
S/N: MM3615073

I'd done a quick parts check and the motor was about $140, give or take. On a service call I figured that'd get marked up a bit, plus at least 2 hours on the labor. That about right? Probably replace the drive belt as long as it's open - anything else? In major metro market so labor is high, figure I'm pushing $400.

My concern is always the control board going, especially after the thing is disassembled/reassembled.

MM3615073 = 36th week of 2002 (it's sourced from Whirlpool; as you probably know, Kenmore is a brand label, products are sourced from other manufacturers).

I found an online source $110 for the motor.

It shouldn't take an experienced servicer more than an hr to do the job ... except for the stacked situation. Access is from the front, so there's possibility it doesn't need to be unstacked depending on the details ... in a recessed location, or clear to one or both sides.

What's your evidence for the motor being bad?

Other normal-wear items to check are the drum support rollers, belt idler, belt, and drum seals. No need to replace anything unless it's confirmed bad/worn.

Friend gave a 35-years-old Kenmore dryer to me a couple years ago (with a 10-years old washer, needed a $15 part) that they were going to toss out. Dryer was "slow," they suspected the element being weak/bad ... but elements typically either work or not, they don't normally weaken over time toward coldness, so I suspected some other problem. Ended up the top-mount filter had a broken handle so it wasn't pushed fully down (or cleaned very often). The unit was clogged with lint from airflow bypassing the filter. I cleaned it up, replaced the filter and rear drum seal that was aged, sold it for $80. The belt, rollers, & idler were in excellent condition, probably had been serviced at some point in time (the element had been previously replaced). Anyway, the point is that the 35-years-old unit had/has some years of good usage left.

Update... Returned from the laundromat (ugh) this afternoon and while putting away supplies, out of sheer irritation I stood there pressing the start button for a good 10 seconds, maybe even longer, purely for the hell of it. Buzzing the entire time. And yep, it suddenly started turning. Opened the door, closed, pressed start and it cranked right up, not a buzz to be heard. Again, and yet again.

Clearly, there's still a problem brewing, but now that it seems that it's intermittent rather than completely dead, does that help with the diagnosis at all?