When do you decide to take profit? A set target, time frame, or other factors?

With market timing impossible

1 make a sound buying choice in the first place

2 hold (almost forever), never sell​​​

For myself, I tend to hold investments long term.

The only times my profits/losses got realised were when:
1. The companies got acquired or got delisted
2. There was an issue with the platform and my positions were closed
3. I got fearful and sold a portion to lock in some profit during the early part of my investing journey.

Other reasons could be to rebalance the portfolio and maintain the allocation ratios.