Remoter,
I'd stay away from the 80-8 that you referenced...If it is not erasing properly on some tracks and not recording properly on others it has any number of issues. You can find one in better operating condition for less if you wait.
One of the more active members in this forum, cjacek, typically offers the very sound advice that model is less important than condition and trying to find local.
I suggest you put those two objectives at the top of the list. If you want to get recording and spend less time tinkering that is...
Also, if long term costs are a concern (because the up-front cost of the deck can be small to the ongoing operational costs of tape and maintenance), then I second the suggestion to look for a 1/4" 4-track deck that'll do 15ips. I had a 3340S a time ago and it sounded incredible, and I have many years of digital work under my belt. I'm back to analog. Not everybody feels that way. Big deal. 1/2" tape is quite a bit more expensive, and you'll be looking for awhile for a 1/2" 4-track and you'll pay a pretty penny for it.
He says it is a tascam but doesnt say the model.
Its a 22-4. That's a 2-speed deck (7.5 and 15ips), 1/4" 4-track deck. It uses the smaller 7-inch reels. The 22 is considered by many to be a good sleeper deal because it shares a lot transport-wise with the semi-pro 30-series...so its kind of a semi-pro deck in prosumer skin...kinda.
Are they difficult to maintain and fix when they break?
Well, that's a pretty big question and it depends on what's broken and what model/make it is. #1 thing to have is a full operations and service manual for whatever deck you get. Between that, passion, a draw to tinkering and help from places like the Analog Only forum you can keep your deck going, learn a lot and have fun in the process. I'm speaking from experience.

BUT, again, that's why its important to choose a deck that's in good repair and has been cared for. I typically lean toward the Teac/Tascam decks because they were well-built, were a good deal in their day and therefore are an extra good deal today, there is a strong user-base, and many parts are still available and Teac supports legacy analog gear even from the 70's pretty well. Fostex made good stuff too, but they are less common and parts and support are much more spartan.
What happens if the heads are worn out?
Heads are much cheaper for 1/4" 4-track, so you can either swallow it and get new heads, or typically (unless the heads are really-really shot) you can get them relapped (reshaped and polished)...you can typically do this a time or two before its time for new heads, but you have to run
a lot of tape past the heads before you get to that point.
Here is a page with pictures of bad heads and some information about head wear...might help you when you are out and about shopping.
I do not know what the difference is between 1/4" and 1/2" except a 1/4"
Well, you know your math...



The wider the tape the wider the track when comparing decks of the same number of tracks...Makes sense right? A 1/2" 4-track deck is going to have twice the track width as a 1/4" 4-track. More track surface area means more oxide particles receiving magnetic flux for a given amount of time. Think of it in terms of a higher sampling frquency in teh digital world, though it really is apples and oranges, but hopefully you get the idea. Like I said above, I had a 3340S 1/4" 4-tack that sounded incredible. I now own two 1/2" 8-track decks as well as a 1/4" 2-track mastering deck. Snobs will tell you that anything less than 2" 24-track is not pro and not worth anything. Big deal. 1/4" 4-track track width is equivalent to a 32-track 2" machine...not far off of a 2" 24-track...this is all stoopid hair-splitting though okay? I've heard really great sounding stuff done on cassette 4-track machines...that's got 1/8 the tape real-estate of a 1/4" 4-track open reel machine (1/8" tape running at 3 3/4ips for the cassette-based unit). drstawl will probably tell you that cassette multitrackers are toys, sound like poo and are as useful as teets on a boar-hog...whatever. Big deal. Get a deck, have fun. You'll like the change from digital. At the very least it'll make you a better engineer and get you in touch with visceral instruments of the trade, like holding the paintbrush yourself instead of programming a CNC painting robot designed to do more in less time more "perfectly"...ahhhh that's better...nothing like mating the art of music and fast-food...that's digital...yum, and I'm not a digital hater. I eat fast food. I like the taste of it and it is terrifically convenient at times...even exciting. It has its place and I appreciate its place, but there is a passion and art that can get lost.
Sure.
But the were built from a different design vantage-point...they were built to last. Properly manitained and utilized an analog open-reel deck will outlast a DAW computer many times over, and I manage a 55-seat computer network domain as part of my job. I build and maintain PC's as part of my job. I know how long they last...I'm surprised that drstawl brought up obsolescence... can't use a MOTU 24i with any computer built in the last few years...not compatible with current PCI buss architecture,
but its funny how my Tascam 48 works like a charm...I buy readily available tape, load it, turn it on and capture!! And its nearly a quarter century old!! Not really sure what you can do with a 286-based PC these days...I don't
think a currently available OS will work with it...

But I suppose drsawl would call the 24i a piece of obsolete garbage too because its max sampling frequency is 48k....MUST HAVE NEWEST...MUST HAVE LATEST!!
whatever...big deal.
Why dont they [make] new tape machines that sound the same and are just newer
Not enough market demand.