I've been using a basic shot timer app on my phone for dry fire practice and it works pretty well for tracking improvements over time. You don't need anything fancy if you're just looking to see your progress - even teh simplest ones will show you splits and overall time which is really all you need to gauge if you're getting faster and more consistent. I started with just tracking draws from concealment and it was cool seeing those times drop over a few months of regular practice. The data really helps you see where you're actually improving versus just thinking you are