Originally Posted by
carnivroar
If my bike cost X dollars, does it make sense to spend Y amount of dollars upgrading it, where Y > X Or is it better to buy a new bike?
If you bought a dirt cheap used bike intending to spend the money to restore it, then go ahead and do it.
Big money upgrades to new bikes never make sense. Upgrading worn out or poorly fitting parts makes sense, but modern bikes are well balanced enough that upgrading just for fun is not cost effective.