We can increase the efficiency of our dry shooting training if we incorporate a non-expensive laser cartridge in our practice.

https://www.youtube.com/watch?v=WgGp-m9er74

https://www.youtube.com/watch?v=QtByYwyBK9g

However, a main limitation of this tool is training only a single fast shot. Also, it is not usable in revolvers. I prefer Crimson Trace Grip for dry shooting. Using this laser sight, we can train multiple shots just simultaneously pulling trigger and pushing a knob at the pistol grip. This practice is also useful to train fast turning laser on just before shooting to prevent uncovering your position. There are different modifications of Crimson Trace Grips for revolvers and pistols:

https://www.youtube.com/watch?v=FEe4AmJLRMo

https://www.youtube.com/watch?v=sEcdZRIj-FY

Of course, the laser sight is much more expensive than a laser cartridge, but I believe that this tool is a good investment because it allows very fast accurate shooting from different positions. For home defense, it may be critical, especially at dark time.