Honestly you dont remember all of your tracks but as time goes on and you build up on your experience you will know what works what doesnt work and which crowds it does and doesnt work for.

There's plenty of times where I'm in a zone playing tracks and things come to mind that I might not have played in a year. Other times you finish your set and be like oh damn I forgot to play such and such even though its the most popular song out

aight thanks for now, if i can come out with the words of my follow up question ill ask>!

If you've pre-edited and rehearsed your mix of a dozen tracks to death, in a desperate attempt at 20 minutes of YouTube fame, remembering them is easy.

If you're a mobile DJ working all the time with thousands of tracks in multiple genres, it's a little harder, especially when using software without a dedicated track preview function.

All the rest of us probably fall someplace in the middle. Sometimes you remember, sometimes you don't!

use cues(label them) and make notes in the comments section to help you remember

I add 25-100 tracks on any given week so it's hard to remember all of the Hot For a Minute club tracks. Organization is key with Serato. You can make extra crates and drag tracks you want to (or should) be playing. For example, I add new music to Serato via a dated folder/crate. I then might take some of those songs and drag them into a new crate for a specific venue or a specific event. This gives you smaller crates of music to scroll through that have had the average, throwaway tracks removed.
That being said, you should have a decent memory of the hot tracks that are out that you are playing regularly. Big part of being a DJ is knowing music. I average 5-6 hr sets when I play and I'll remember whether I've played a track at all that night, or even the week before. Scrolling through your "event" crates will refresh your memory, as long as you do the prep beforehand.