I only plant one per cell cause I am terrible I HATE thinning and throwing away a good plant

Scissors are your friend.....I thin.

But I'll add that I have pushed the cell contents out from the open bottom of my deep-cell trays, divided and repotted seedlings that seem to be doing exceptionally well when its something I want more of, or want to share.

I rarely sow less than 3 or 4 seeds per cell, unless a larger seed that is somewhat fool proof, like sunflower, or when it's a seed where I've only been able to acquire a very few.

I usually let them grow out a little (first sign of real leaves?) -- and then I take that cell out and divide into two pots. Kind of depends on what it is, though...there are things I can easily give away to friends and others that aren't feasible for them to grow in big city apartments. There are also plenty of things I can't plant more than one of on my property -- like any plant that gets enormous (9x9, etc.). Then I wait until I see one doing better than the other and snip.