I HATE measurement questions...I had a pair of RL pants and a skort, same sizes for sale on CL, can't they read the size?????
IMO, you may hate it but it's actually very important to the buyer. The size tagged on the pants (or whatever it may be) does not always fit the same. It all depends on the cut/style. I always post measurements in my descriptions so the buyer knows exactly what they're getting but at the same time, I also mention that all measurements are approximate.
If you don't post measurements, buyers can just blame you for not posting measurements and if they have buyer's remorse, they'll say it didn't fit, etc. (Also, when I say "you", I don't mean you directly but just in general )