ATA TRIM isn't a longevity thing, it's a performance thing. When windows deletes a file, it simply marks that space available for overwriting--the files aren't actually purged. That's fine for mechanical disks, because they don't get any slower when that happens. It's bad for SSDs though, because write performance is directly tied the fullness of a NAND cell.

If NAND cells the drive wants to write to are full with 10% legit files and 90% bullshit (unpurged deleted files), it has to copy all of the legit user data to cache, erase the cells to clear the 90% useless data, modify the cache's data with what YOU want to write, then copy it all back. This is called write amplification, because the amount of data being moved around is an amplified amount, relative to the data you're actually looking to write.

The ATA TRIM command deletes the file from the NAND cells the minute they're deleted in the OS, so the cells only ever contain active user data. The only time it would have to perform this read/erase/modify/write action is if the cells it wants to write to are 100% full with real user data.

Obviously this extra file juggling does have some longevity considerations, but they're minimal. The real benefit of TRIM is an SSD that does not sharply degrade in performance over time through simple usage.

As for your longevity questions, i.e. "How long do I have before this drive is dead?" That is exactly what I am looking to answer and, possibly, clear the air about. I don't have a clear answer for that yet, because every drive controller has a different write amplification factor that can be as big as 40:1, or as little as 1.1:1. If my research pans out, I will be able to say "These SSDs are good for XXXGB of data per day for XXX years." That is my goal.