If you are serious about firearms and self-defense training, you need a practice or facsimile weapon for ongoing, safe rehearsal of your skills. Dry firing with your actual firearm can be done safely, but civilian force-on-force training with real weapons, even with empty chamber indicators, is near criminal negligence.
Fortunately, there are a ton of awesome options out there these days that can help you dive into more realistic training as a civilian. You have the tried and true Blue or Red guns, airsoft, and common marking pistols all available to make safe force-on-force training a reality. LE and professionals have access to more realistic systems like Simunition, but that's an article for another day. We're going to focus on airsoft this time around.
The modern day quality of airsoft weapons and their weight and size give us near identical copies of real firearms. You can likely find a replica of your real handgun easily so you can train very realistically for a fraction of the cost, even if the trigger isn't exactly the same. These systems can also work with or without BBs, allowing for slide reciprocation without endangering nearby people or valuables. These facsimile weapons can be used for demonstrations indoors and out, skills development, manipulation drills, and even introducing new people to firearms.
The nice thing about force-on-force with airsoft is that the safety gear required is minimal and fairly inexpensive. You can find good quality stuff at airsoft stores, online, and even some of the big box stores. Safety gear can be added or removed depending on how tough or sensitive you are (neck and groin protectors, gloves, etc), but eye and face protection is an absolute requirement. Nobody wants to catch a BB in the throat!
I love my airsoft pistols for dryfire. I take a coffee stir stick or something similar and cut it to size and wedge it in between the magazine follower and the top of the magazine. This allows the weapon to cycle and function without firing a BB because the slide lock won't engage. The repeated reciprocation makes practice more realistic, especially for in-battery reloads and trigger press exercises.
The magazines are the weak point of the system as they are much more fragile than the real thing and can easily break if dropped wrong on a hard floor. Depending on your model, the magazines may or may not be expensive to replace but probably lean on the pricy side.
You can use scaled-down targets in your basement or yard to practice as if you were at the range. Since airsoft projectiles have nowhere near the same accuracy and range the real thing, smaller targets help to simulate distance. When you consider that most airsoft guns have very little recoil, you can almost see your maximum possible speed on some drills, which is what you should be working towards with your real firearm. Don't run until you can walk though - always stay within your capabilities when shooting live.
Ammo costs are coming down these days, but BBs are still a fraction of the cost. Think about the savings practicing over the long term! If you are introducing someone new to firearms, training weapons are a great way to solve nearly 90% of early issues such as manipulation, sight picture and alignment, grip, stance, and more before heading out to the range and wasting ammo.
All that said, live-fire training is absolutely a must. While facsimile weapons can help with tactics and technique, truly understanding recoil management, trigger control, and grip among other skills, requires live-fire.
On a parting note, “playing” airsoft wars/battles/games has value and is a ton of fun. You can learn good tactics and technique when properly set up and someone knows what they are doing. If you get smoked quickly with several airsoft rounds because you thought you were the Terminator or Robocop, you will learn through pain and it is normally self correcting. In SE WI, both The Siege and Airsoft HQ run airsoft events and they are a good opportunity to check out your skills... or just socialize with some like-minded folks.
As always, stay safe and hope to catch ya on the range whether its live-fire or airsoft! -'Ski