By your 40s, yes the 2x versions are often in order and I use them for both Ammo and TUTH but I do still keep a bottle of the 1x TUTH for steering or tuning mixes. I’ve not felt the need to go for the 3x TUTH yet.
And for Ammo, if you get the standard, FF21 scented version, 2x can also be a useful scent control measure as its pretty robust. The World Edition or Blue Summer scents are not so strong.
The best way to determine your working dose is to follow the “Sweet Spot” guide in the following thread for each phero individually, although it can be a challenge with TUTH due to its overtness: