Why there is a weight used to train a new custom model? and what weight should be used?

[kronee0516]

as the title

should i use the trained weights for next time train
1 for 2 , 2 for 3 until the result satisfy my needs?

or should i always use the same weights( yolov5s.pt) as the training weight?

or it is not useful at all , just ignore it?

please help