$20 pays for about an hour of extra productivity per month. If you get that much, you have your ROI.
Is that an hour not spent googling? Is that an hour of extra energy because I didn't need to sift through a 5000 line log dump? It's pretty good.
The actual value I get from agents is it's a rubber duck+Google, not that it writes code. It's also a journal of my previous train of thought. I can 'code' while in the train now, or 15 min before a meeting instead of blocking out 4 hours.
It's closer to 2x for me, realistically. But anything more than 2 hours per month seems greedy.
But that 2x productivity doesn't mean I get twice as much done. It means some of my colleagues get laid off, some interview/freelance/side hustle because they're worried about getting replaced by AI. The whole mess means return to office which ends up in 0.5x productivity and 1x net productivity.
But we need a few less engineers and managers so I guess that $20 and the $20000 office space is worth it in the end.