As for the recondition of a TPS, Volvo sells a kit.

When I got new tires for our 2008 XCF70, the sensors were tired - My tire shop had replacements for much less than Volvo's ones.

Actually they are nicer than Volvo;s - the stem is rubber with a brass tip, they look just like regular tubeless tire valve stems - they work fine. I have since e rebuilt the old Volvo sensors and have then for spares.

BTW - My 2008 had a slow leak and the sensor alarm went off - We used our other car that day, and the next day MY KEY FOB WOULD NOT UNLOCK THE CAR! My dealer had never heard of that happening, but it happened to me three times.

My son-in-law, a Suaru tech told me that it made some sense because the door lock and the tire sensors use the same computer - they both are wireless.

Hugh,
The TPMS you have has a transponder inside which sends the computer the actual tire pressure. The transponder takes very little electricity to work, and it should work for at least 30 years, if not longer.

The 'new' TPMS system tracks tire rotation. A deflated tire will turn faster than the others and the ABS will turn on the warning light when it detects an anomaly. The ABS will not know which wheel is low, that is up to the driver to determine. It is a much cheaper system.

There are TPMS systems on the after market which will tell you what each tire pressure is and also the temperature of the tire. Cost is under $200, labor to install is additional.
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Keeping it running is better than buying new

Hugh, My wife drives a 2014 (85K miles) with the TPMS and it has correctly activate a few times over the years. Never replaced had to service it in any way. Recently The tires were replaced and I noted on the bill " TPMS valve reconditioned $5.95.......I don't have any idea what that was for, but not
worth following up on.

I would talk with a major tire store and they most likely know the
answer to your question.
Art