Thinking ahead ... very wise move!
This would have been a very different conversation 10 years ago.
When it comes to VCRs, the only thing that really gives out over time are the rubber belts and the pinch rollers. The lube inside starts to turn to sludge after a decade or two, also.
When it comes to wear on a VCR (or computers, or any number of electronic/computer devices), a lot of it is actually user-induced death of the equipment.
- Are you a smoker? If so, you can pretty much plan to throw the equipment away in 1-3 years. It will be ruined from the mixture of chemicals given off by the tobacco stick, and what's natively in the air.
- Is it dusty? By this, I refer to the desert, where there is airborn particles.
- Is it humid? If so, then expect dust to start sticking to the machines. It will need to be scraped off every once in a while.
- Is it climate controlled? Severe heat and cold will harm the equipment.
- Do you plan to clean it out (blow it out with canned air "duster") on a 6-month basis? Or will it just sit there uncared for?
- Will you be running the VCR non-stops 24/7/365, or just as needed? Maybe 365 tapes per year? (One per day, at most.)
As dust is dragged across the capstan, rollers, heads, etc -- that's where damaged happens.
This is aside from the damage caused by tapes, be it oxides shedding, or the abrasions of simply dragging a mylar/polyester film across the ferrite heads. This kind of wear takes time -- more than damage by dust/debris.
How many heads would I suggest?
- If you are a non-smoker is a normal environment relatively free of excess humidity/dust, plan to maintain the machines every few months, and are a light to medium user, you may not need any heads at all. You can buy one if you just need to feel extra safe.
- If you're a chain smoker living in a beach condo in Arizona, planning to run at least 3-4 tapes per day, you'd better buy a box of heads (or more), maybe even a few extra machines!
- If you're in between, then act accordingly.
Years and years ago (1990s), stuff was hard to find. It was all overpriced, controlled by broadcasters and VCR shops. These days, 2000s, you have
eBay and craigslist and others -- there's no shortage of "for parts" (or even "like new") VCRs of similar make/model.
What is used here is all backed up with not just parts, but whole extra VCRs. In some cases, the older now-broken VCRs are kept in a closet for parts. Some of them are modular, such as JVC S-VHS machines -- many of them share parts across models. Pieces out of the 3800 fit into the more expensive 9800 (or 9600 or 9900). Not all parts, but some.
eBay is a good place to look for spare parts, especially the "for parts, as is" machines. Victor Japan (JVC Japan) may be good, as well as JVC USA -- maybe even try local VCR shops. Ask broadcaster engineers in your area, local TV station operators. JVC Germany, maybe, as that's where UK PAL machines are built.
Portions of my JVC HR-S7965EK UK PAL (made in Germany) machine look the same as an inexpensive JVC HR-S3800U USA NTSC machine. I quickly looked through the front door at the rubber bands, rollers, capstan.
I just pulled out an old family VCR from 1981 yesterday. It works fine. It's kept because of it's fully manual tracking controls.