Well a while back, i paid a full years rent in advance, this was more of convinience and trust rather than any 'requirement'. I was a student then and was sure i was going to leave in the house for the year, and the landlord and I found it more convinient that way. Because of the trust they even gave me discount because i paid all upfront....any work breakdowns repair required e.g boiler work would be done in matter of days. So if if you like it and are sure you want to live there for at least six months then, yes i would pay for it in advance.
Paying upfront for six months is not the norm, unless you plan to live there for at least six months. Usually, contracts require one months notice before you are free. Also, you would kinda be stuck if you decide to move as the landlord may not cough up the money back, say if you decide to move just a couple of months after moving in- e.g if you had to move cause of a new job...
As an example, i have come across someone who rented a flat for a month and decided to change uni and ended up paying 3 months at the old house (at old uni) and another load for the new house at my uni. He dint want to pay for the 3 months at the old place, but the landlord kind of made him to.
......so the shorter your notice period you would stand to gain if you decide to move later.