what do you want to practice?
Chris -
Practice is good -- if you know that what you are practicing is good technique. Otherwise you are going to be establishing muscle memory for bad technique.
I once thought I could dryfire and improve my technique. Then somebody asked me how I know that I really was hitting what I was aiming at. That shook me up enough to invest in a LaserBlater, and later on in a Bullite. They are training aids at best, but then so is ammo fired at the range. Over the life of batteries they both work out to a heck of a lot cheaper than the cheapest ammo you can find. ($6 for LaserBlaster batteries good for somewhere near 500 shots = 1.2 cents per, and the Bullite = 2.75 cents per for 10,000 shots.
I have no financial interest in either product, except that I have paid for them and hope the companies do not go out of business if I ever need customer support/repairs.
Besides, I can do all sorts of drills with a laser trainer that my indoor range will not allow, even if I am the only one there. I can do stuff that would not be completely safe on the best of outdoor ranges. But those scenarios are based on real-world issues that others have had to face.
And best of all -- how else can you ever practice clearing the homestead in your undies while proving to (insert name of person/species here) that it really can be done in a dignified manner? (No, you do not want to know, and I'm not dumb enough to ever tell.)
stay safe.
skidmark