Splitting Dahlias

Janie B

I have grown dahlias for several years now, sometimes I've lifted them, other times I've left them in, but this is the first year I have split them. (I was on the point of chucking out a New Baby (!), but decided to split it, now I have about 7 of the dratted things! Think I'm going to see if they want them at the plant stall at the Open Gardens...). Anyway, I was wondering, is the only reason for splitting them to provide more plants? Or does this in some way help rejuvenate the plant? Would it harm the plant if it was never split, just kept and got bigger and bigger...? Thanks. 

Lyn

I had a huge one, always left in the ground, but it did start to have fewer flowers,  I teased it apart and got lots of little ones off, all potted up now. 
So, whether it should be done or no, I’m hoping it will rejuvenate the old plant. 
Time will tell.