Nice to see a satisfied customer. Making big holes in targets,reactive or otherwise, is fun.
Now on to other things.
The 9mm. is cheaper to shoot,granted. What you do it from is the subject.
The PT111 Mil/pro is a fine gun. If the gun is going to be used for primary CCW then that's fine. These will work as a home protection firearm as well.
Shooting a larger size gun is easier than the the pee wee guns.
Are you going to try IDPA,IPSC,pin shooting, or other competition? Competition in any of these is fun and makes one a better shooter if the effort is put forth by the shooter. If so then a larger 24/7, OSS, PT 911, or PT92 might be something to consider.
24/7s are kin to the Millennium Pros PT111. Therefor alike and easier to get aquainted with and stay that way.
These can double as home protection gun. This goes for other brands of handgun also. It's easier to stay proficient with the larger guns as well.
Not to say it can't be done with the PT111 Millennium Pro. It can. Just depends if versatility is needed or a want as to which way to go.
As an example the Ruger P95s come out more and are shot for competition and are more likely to be the house gun. CCW carry doesn't exist here in Wisconsin so the PT111 is used for carry on the property,answering the front door at o'dark thirty at night, or under other discreet conditions.
I procured the Rugers because the Tauri guns were hard to find or procure around here way back when.
So a centerfire full size or slightly smaller size might be the ticket.
If shooting cheaply is a must then getting a good .22lrf pistol of the Ruger MK.III , 22/45, a Browning Buckmark, or something similar would give you quality range time at a much lower price than with the centerfire guns. Centerfire ammo prices are going to be high for a long time to come.
Consider the .22lrf pistols as understudy guns to the cneterfire ones. In other words it's possible to get real quality range time practice in with the rimfires.
These are just being put out for consideration.