By sowing two seeds per cell you can pick the healthiest of the two and cull the smaller. This helps enhance your chances of getting big strong plants.

SCG

Agree plus it also insures germination in each cell so you don't end up with empty cells. But how many seeds you sow in each cell all depends on the size of the cells too as they come in many different sizes. For example in a 4 cell pack (2.5 x 2.5) you can plant 20-30 plants of some things. Then you just transplant them all out of it into individual cells or other containers. Plants sold in cell packs were not germinated in those cell packs but in full trays.

Dave

While that makes sense, last year, both seedlings in a lot of the cells looked fabulous, and it was hard to choose which one to kill. I think for me, I'm more okay with having an empty cell than removing a perfectly healthy seedling to discard it. That is just me of course lol. As long as 1 to a cell is not detrimental to the plant somehow, I'm happy now that I chose the 1 per cell method. Thank you both so much for your answers.

No need to kill the extras. Just transplant them into other containers..

Dave