I have always preferred to pay monthly instead of upfront payment. The reason being, if I am interested in buying something, I prefer it to be monthly because it provides the incentive for the product owner to keep it updated. Of course if the product is such that it is a one time deal and does not need updates, then I would prefer to pay upfront. But for things like software i prefer monthly instead of upfront.
But there are valid reasons for paying monthly instead of upfront.
So what do you prefer? And why?