I hear it time and again that old 7.5" reels are not worth wasting our money on. They're not prohibitively expensive, but the postage costs do drive up the bottom line for us located down under - because the vast majority are in the US.
I've been ignoring the advise, and buying anyway. My experience has been mixed, I've received some crap tapes that sound ordinary from years and years of wear and tear. But equally, I also have some real pearlers. I have enough good tapes now, that my position is, ignore the naysayers ,,,,, if you want to spend your time and money hunting out old tapes, do it. Not all will be good, but not all will be bad.
I find it incredibly rewarding to find a great sounding old tape. It's a real treasure.
For those tapes that have been a good score for me, I'll post about them in here. Disclaimer, if I post about a good tape, it doesnt guarantee that the same title sourced 2nd hand will also be good for you. It really is a lucky dip. These tapes are 50 odd years old, and it all comes down to condition.