I've not had any sticky/shed with pretty much any of my 499 stock...and the 911 is like silk.
I do have some NOS 456 that I have yet to put to real use, but usually when I get some NOS reels, I will check the first couple of minutes worth of tape just to see where it's at...and the NOS reels have all been solid.
I do also have some used tapes that were acquired over time...mostly 499 and a smaller bunch of 456 , and of those, without any knowledge of their history, I've had mostly 456 reels that came up sticky or light shedding, and only a few 499...but even most of the 499 used reels were all still quite clean. If anything, they needed a couple of passes from being spooled and unused for a long time...after that, they ran like new.
I have recorded on the used tapes without issue...even though I have NOS reels available.
I don't have a problem with getting a small percentage of SSS tapes from the out of production stuff (used or NOS)...but overall, I have not been compelled to buy new production tape because of SSS concerns.
I've gone through every single reel of tape, and I mark them all AFA their condition and if they are used or NOS. Also for me, the tape is primarily for tracking, and then it's transferred to the DAW...so I'm not concerned about long-term archiving on the tape.
The recordings I do stay on the tape (unless I ever get to a point where I need to reuse a reel for new stuff, which I don't see happening any time soon)...but I have no concerns about any of the tapes going bad and losing the tracks.
I think I mentioned in another thread that I just score a baker's dozen of NOS Emtec 911 2" reels...and they are all clean and silky smooth...I look forward to tracking on them.
At $300-$400 USD for a reel of 2" ATR or RTM tape...before I buy either of them...I'm going to get full use out of my NOS and used stock of 456, 499 and 911.