I'll share my approach on what sm has posted...
I have an existing long wish list of watches to which I add on as and when I come across latest reviews or SIHH/Basel novelties. Based on my funds, I'll never be able to fulfill my wish list in my lifetime.

No target of how many pieces per year. As and when I come across a piece on my list at a price I can accept, I will get it if my funds permit.
I usually don't sell a piece not unless the replacement is a similar manufacture having the same complications but technically better or emotionally more appealing than the original then the original piece has to go, otherwise it will sit there and never get worn again
In one grooming course donkey years ago, they say that your main watch should cost at least 1/3 of your annual salary, if not more..

So far I can't bring myself to spend that much yet.
No fixed number of total watches although I'm repeating the same mistake over and over. Prior to 2010, I decided to reduce my total collection to not more than 12 watches that had real horological & economic value as well as emotional attachment to me and to sell the rest. Since then my acquisitions have accumulated to about the same number as pre-2010, i.e. a different watch per day for > a month

On paper its easy to limit the number of watches but being human we sometimes are illogical and are ruled by the heart rather than the head.
No heirloom as no one to pass it on to but will sell everything when I'm too old to read the dials except the 1 piece I'll wear with me

Only bought a watch to celebrate my first job and none since
Addicted is an understatement...... obsessed is more like it