So, the ammo shelves in your favorite gun store are about empty are they? Well, try to be patient. The situation will change, eventually. In the meantime, however, your practice regimen has about gone to pieces. Why go to the range if you have nothing to shoot?
The solution for the defensive shooter to stay in shape during this ammo crisis is to spend more time in dry practice. Some years ago, one of the International IPSC teams was so low on ammunition, each member could only fire 10 rounds per month. The rest of the time that team spent in dry practice, and they went on to win the International IPSC matches that year.
With dry practice, the defensive shooter can emphasize the basics. He can work to perfect his pistol presentation. He can work on acquiring a quick sight alignment and smooth trigger press. He can work on sensing the trigger reset and staying on the trigger during his drills. It also doesn't hurt to go through the various malfunction drills. Most of all, he can work to rid himself of those bad habits that enter into our defensive-shooting techniques.
Find a place in a suitable room of the house to practice, and determine an aiming point. The standard light-switch plate serves quite nicely. Personally, I try to practice for no more than 15 minutes per evening, and try to do that at least four times every week. If you pay attention to what you are doing, dry practice doesn't need to take very long.
Speaking of paying attention to what you are doing, please make sure your old pistol is empty. Your wife, family and probably the neighbors will really appreciate it. It's a really smart idea to start by taking all live ammunition into another room. If you are practicing with a partner, do a manual and visual check on each other's pistols, just to make sure they are completely empty. And, once you have stopped and recharged your pistol with live ammo, make it a habit to insist all dry practice is completely for the evening. At the least, negligent discharges are very embarrassing—they can be a lot worse than that.
I predict when you get to the range for a session with your carefully budgeted ammo, you will find your dry practice has paid off. And, by the time that ammunition is more readily available, you will find yourself a better defensive shooter thanks to the time spent working dry.