Valid point, and for most people on here who live in Oldham it'll be McMahon and Abrahams who will retain their seats. At the last election, I had the choice of voting in Oldham or in Sheffield where I was a student and I had a chance to vote against Nick Clegg - the man who promised that I wouldn't pay £9000/year for uni. So I voted against Clegg (who won but with a slashed majority), where I felt my vote had more of an impact. The system probably needs changing, but that's another argument for another day.
But... if people in safe constituencies like Oldham all vote for Labour because there's no potential for swing, then there never will be a change. Surely there's always a chance if the candidate is good enough? I'd rather my vote went to who I believed in rather than who is already in the seat.
My main hope for this election is a high turnout. People have a lot to say about Brexit/Tories/Corbyn, so do something about it. If you can vote, register, do your research, and vote on June 8th. I'd never tell anyone who to vote for, but I'll always tell people to get out and vote. In such an uncertain, turbulent time where we're leaving the EU, it's so important to have your say.