In reply to Reach>Talent:
One thing to consider though is on 8mm having two seconds or climbing soley on one rope and then the other is not as safe (due to getting cut more easily). Also if you fall off a lot they will loose elasticity faster.
Personally my next ropes will be 8.5 mm but thats because most my climbing will not be in winter now and doesn't involve a lot of climbing with long walk ins now i don't live in scotland.
The longevity of the ropes won't factor in to it as they last long enough.
I climb less trad now I live in the SE though probably on average 15-20 weekends a year or something.