Most good/modern SSD's should have built in capabilities for at least the bare minimum of garbage cleanup
You used to hear all kinds of horror stories about people who threw a SSD into their PS3 and found their whole system grinding to a halt within a year.
"Enough" is a relative term and is up to you to decide. The alternative is significantly less performant coupled with unpredictable reliability (outside of expensive enterprise options), but a higher overall lifetime.
People don't tend to want to have to actively maintain their old tech any more than they absolutely have to.
Though I do think that if one is using old tech, they should be aware of the pitfalls. There was a good run of the capacitor plague, for example. I avoid this equipment in general as I don't have soldering skills (but man oh man, I would love to have a working SE/30! People trying to sell repaired SE/30s on eBay for $1400USD!) to repair them. I know the VRM on my G4 Cube can potentially have issues, as can the power brick. Fortunately there are small batch available replacements should I need them.
In practice, all SSDs have internal capacity greater than the nameplate capacity exposed to the OS, so all SSDs start with a reasonable amount of spare capacity; enabling TRIM merely increases the available spare capacity in proportion to the number of currently unused logical blocks vs. never written logical blocks — blocks outside all allocated partitions (unless written by something other than a filesystem [e.g., manually, or via a naïve disk imaging, diagnostic, or RAID rebuilding tool]) and blocks that allocated filesystems have never had the need to use (unlike SSD firmware, traditional filesystems don't practice "wear leveling" when allocating space, so, e.g., a 1TB filesystem that has never contained more than, say, 100GB worth of data at any point will probably contain a large number of LBAs that have never been written, independent of how much data has been deleted and overwritten).