Amp longevity, if well taken care of --the risks of purchasing used equip.

Many years ago I bought a pair of speakers at Stereo Exchange in Manhattan. Dave Wasserman, the owner, mentioned that the speakers sounded especially good with Conrad-Johnson amplification. I told him I was using a pair of McIntosh MC60s, and an Audio Research D51 amp as a backup. That drew a huge guffaw, and he said “I love a guy who’s got a backup amp. You clearly don’t need the CJ gear.”

I’ve had the Macs since 1979. They were manufactured in 1959 and 1960. I’ve had only two problems over the years, so I probably don’t need the backup, but I do sometimes swap in them D51 for a different flavor. The D51 probably dates to 1971 or’72, and I’ve had one issue with it. So yeah, older amps can be quite reliable. But I don’t know anything about Bel Canto. 

I purchased my Mac MC240 (circa 1967)

around 1995. Still going strong making wonderful music. 

The parts that age soonest seem to be the caps. Inspect them for swelling and discharge. They can also be measured with a multimeter. 

Caps are relatively cheap to buy and not difficult to install. 

If you are somewhat handy with a soldering iron it's a fun way to really get to know your amp. 

I'm running a pair of MacIntosh MC2100 amps that were manufactured in 1975.

Other than a recap and general cleaning I have not had to do any other work on these - and no problems with them either.

Normally, 10 years old is nothing for a quality amp...  Using older Vintage amps periodically can save the caps.  Especially, if they were high quality, long lasting caps to begin with...  Amps that sit for decades can have the caps dry out - even high quality ones....   If you are worried, you can ask for very detailed pictures, so, you can do a visual check of all the caps to look for swelling or leaking on the boards and you can check the reputation of those particular caps. You can also ask for a picture of them checking the DC offset on the speaker terminals with the amp on....  This is a super easy check and you will want to see the DMM display and the amp connections in the picture.  The lower the DC offset voltage, the better condition the amp is in.  The first time firing it up, you also might want to use a Variac. 

Checking the DC offset on an amplifier requires a digital multimeter (DMM) to measure the small amount of DC voltage present at the speaker terminals while the amp is on with no input signal. Ideal DC offset is close to  0 mV with readings under 20 mV — 30 mV being considered healthy and safe for speakers