How many worlds/save files do you have?

I was going to say that I have one main save but that's not entirely true. My first game was affected by so many glitches that I finally had to retire it in 2016. The characters from the first save were started in a new save but I found out that they were glitched with something related to the Problem Child achievement. Apparently, a townie teen had maxed the Mischief skill which gave the save the achievement and the notice popped up for each active household. So, I started them again as new Sims with no skills or careers in another save. That save got glitched when a change was made with how saves were made.

At any given time I only have one save in the saves folder so they don't accidentally overlap. I use my original Sims to test things that I'm interested in or curious about. I start with no more than 2 active Sims in case something goes wrong.