From what I can find, the Pro-2032 may have been produced from the early to mid '90's so it's getting a little long in the tooth. It was made for Radio Shack by GRE, probably in Japan, and would appear to be of good quality for its day.
The major age related failure-prone components are electrolytic capacitors. The power supply is internal on the 2032 so isn't easy to replace like one with a wall-wart. If there's a noticeable hum when in operation I'd suggest using a good external, filtered and regulated 12 volt power supply with a fused mobile cable (optional on that scanner). The internal power supply will then be bypassed and you may get cleaner audio out of it. You need to listen closely with headphones or an external speaker to determine if the level of power supply humming is objectionable.
From Radio Shack's manual:
Connecting to Vehicle Battery Power
You can power your scanner from your vehicle's cigarette-lighter socket by
using a DC adapter (not supplied). We recommend RadioShack Cat. No. 270-
1533. The vehicle must have a 12-volt, negative ground electrical system.
Connect the DC power cable's small barrel plug into the DC 13.8V jack on
the scanner's back panel. Then plug the other end of the DC power cable
into your vehicle's cigarette lighter socket.
I would expect any consumer electronics to last at least 5-10 years in normal use. However, yours has been rescued from the 'way-back' machine and has been powered off for over 10-15 years so will probably only have degraded slightly compared to those which have been powered on all that time. It's still going to degrade, however, even in the box.
What I'd suggest is this. Turn it on and program it for an active, nearby set of channels then listen with headphones to try to detect a low hum from the power supply. If present, find yourself an alternative power supply. Otherwise, just use it and enjoy your find. It can probably have the capacitors replaced if the hum is bad but it may be easier/cheaper to just use a modern switch-mode external power source. Or it may run perfect for a long time. The point is that the failure-prone capacitors may cause humming.
As a reference, I have two 20-something year old hand-helds (A Pro-30 and BC-100xlt) that still operate; though not well. The Pro-30 has 3 coin-cells for memory backup and they leaked - that's the only problem as far as I can detect other than the aging wall-wart's hum. Still worked until a few weeks ago as my RR feed source till it mysteriously lost its audio, but I suspect that was memory corruption due to the corroded coin cell terminals. Likewise my BC-100xlt still works though it's been dropped innumerable times and has a hiss in the audio due to the drops misaligning the tuning coils etc.
As a feed-source you may need an audio isolation transformer between the scanner's external speaker jack and your sound card. Many Japanese scanners have non ground-referenced audio amplifiers so be prepared for this. It'll also help eliminate or reduce hum as the cheap transformers in these ground loop isolators don't pass much below 200 Hz.
So a well-cared-for scanner that's been stored for several years in its original box should work fine for 5 years or more in my educated opinion. The power supply, however, is suspect but other than that I'd feel fine setting it up and just letting it run. Figure another 3-5 years of reliable service powered on 24/7 and keep your eye out for deals on refurbished or used models to replace it eventually.
