As with all things, it depends. I use CR as a base guideline and then adjust for the party. If you have a group of 4, use 6-8 encounters per long rest, minimal magic items, average group tactics, decent monster/encounter strategy, point buy or average rolls (no rerolls/statistical anomalies), etc then it works decent. Throw any one of those things off and you may have to make adjustments.
Don't underestimate the number of PCs and action economy, especially versus solo monsters. At higher levels, solos don't really work particularly well (I'm not sure they have in any edition) so you have to add minions, tactics, hazards or some combination therein.
In my experience, I had to increase the party be 2 "PCs" for one group to balance out right, the other using kobold fight club things worked fairly well with a straight calculation.