Anyone into cassettes?

If you are using old tapes i.e. 30-40 yrs old there are a number of things to watch out for.
Although the mag tape portion is absolutely fine and probably sounds as good as it did on day 1 (subjectively)sometimes the leader tape can lose it's stickiness (rather like dried out cellotape) and the danger here is that the sudden shock of hitting the end-stops, either by playing or winding, can cause it to become detached. I wouldn't have too much confidence in the splicing kits sold on e-Bay if the kit's leader tape is of similar age.
Gently hand winding and avoiding the machine's automatic stop sensor is recommended as a preventative.

Next up is the pressure pad at the tape head. As with the leader tape these can drop off altogether or lose their tension (you'll notice immediately because tape speed regulation will be all over the place)
Tape jamming is rare and can be a problem if it happens in the middle. Long time ago I used to have a manual winder for the awkward ones that motors simply couldn't drive beyond that point.
With less severe cases it could be solved by fast winding to the opposite end then rewinding completely to re-layer the tape. Sometimes the housings and mechanisms were too cheaply made.

FWIW I've found the most reliable mechanisms and construction are in the Deutsche Grammophon tapes. Next are Decca.
EMI & Philips were sent by the Devil. ;^)
Hope this helps.

Speaking of the pressure pads falling off there are some very informative YouTube videos that explain how to reattach the little feller or in case It went Missing in Action how to replicate the felt pad and attach it. I have reattached five of the felt pads in the last few months. It's a piece of cake.

Good advice Geoff :)
I lost one of those pads recently and never did manage to find it - it vanished completely!
Don't think the cassette itself is too critical or fussy about the attachment. it doesn't have to be symmetrical just reasonably aligned and as long as it barely covers the edge of the tape.
DG always used massive pads. (They take no chances ;^)
Even if they did become loose you'd probably never know as they're wedged between the top & bottom of the housing

It's cost effective to salvage or transcribe those old tapes (digital transcripts are surprisingly successful at capturing the essence of the tape recording - and I say this as an analogue die-hard). The level of musical involvement & insight gleaned from these old tapes is incredibly rewarding.

(Just try costing replacement CDs on the net. For the rare ones you could be looking at hundreds of $$$/£££ per item. You are absolutely right. Salvage is well worth the effort)
All the best!

Thrift stores are a great source of premium quality tapes ... used of course. Just make sure the tapes aren't broken, then use a tape erasure (available at Radio Shack). I use the large eraser intended for VCR tapes. As a side benefit, you can also use the tape erasure to demagnetize your CDs to reduce the digital grain. If you buy the used tapes, just for fun, take a listen to what was recorded on them by the previous owner. Its amazing what crap people record and listen to .. even on the premium tapes.

I'd better mention the finest cassette machine ever made the Studer Revox B***studio..(before it we used the Nakamichi decks) the thing is crystal clear and smokin with those great TDK XG tapes.