" if it is in the budget buy a timer "
I have one that I use (CED7000). I really like the par time beep mode. It is good to use to let you know how far off you were from where you want to get.
" it's a MIND ERASER "
It really is. We shot on Saturday. I loaded 3 rounds, put 3 in replacement mag #1, and 3 in replacement mag #2. Each time the magazine went empty, it caught me by surprise.
I consider myself an educated man. I cannot believe that I could forget that I only loaded 3 rounds, not once, but TWICE in 10 seconds. The timer adds a crazy element to the practice.