Depends on what you do. The last I knew, there were several programming languages that used RPN internally, and as pointed out above there are a few that present that face to the world.



Calculators are mostly a dead end these days, and RPN has gotten quite rare in calculators so that wouldn't justify any real effort.



Unless you specialize in writing assemblers or compilers, or focus on one of the few RPN calculators available there really isn't much need to know RPN.



That said, it should take you 10-15 minutes to learn 99.9% of what you need in RPN. Not much longer to become proficient in calculator operations. The great thing about RPN is that it is totally consistent. No need to memorize special rules for how to compute x to the y power as is usually the case with algebraic calculators.



Why not put it in your toolbox?