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
