I think worthy of note, I don't believe Los Angeles Police (LAPD) switches all 8.967 sworn gun carriers over each time it switches to a newly-issued firearm make & model.
I believe existing issued firearms are used until someone makes a decision the individual officer's handgun needs replacement, although this could be a thousand officers at a time. I don't know how long the older guns would be kept. I suppose it is possible I'm completely wrong and 8967 handguns (and some spares, leather gear, optics, & maybe lights) will be bought and issued to each officer at a periodic qualification.
This doesn't include any special units with special approvals to carry STI or 1911-type handguns.
I also think some of this depends on how well a Chief can obtain funding for larger weapons buys. Heck, maybe LAPD was able to get enough funding (city council; Federal/state grants; to buy 9000 new guns with supporting accessories. That $180/gun price might be a mere $1.6M and don't know what holsters, mag carriers, optics, and lights might add. I don't know how that $180/gun price details worked as someone mentioned; &/or does that price somehow include trading in old guns.
Training costs on a new handgun with its accessories would also need to be budgeted in somehow, too.
Where I worked all ~600 of us got the Glock 22gen2, then the replacement G22gen3, then the G17gen4. I think that department is still using the G17gen4 guns. Newly issued guns were swapped out at the LEO's next qualification and these quals were 2x/year. Personally-owned guns used on-duty would only be for our backup guns, if any individual wanted to ever carry one.
Perhaps someone with more knowledge than I've got can elaborate on how LAPD actually works with issued handguns and to what extent personally-owned firearms are allowed and monitored, if any.