Originally Posted by
Jean-Baptiste Legrand
Sometimes those fare differences can be so crazy it can be cheaper to just toss the ticket and buy a new one home on a different airline...
It is unusual for return tickets to be refared at current prices – the norm is (used to be) that they would be refared at historical prices from the date of last ticketing. Thus, as long as the same fare class (I probably) is available, and as long as you are returning later, not sooner, the worst that I would expect would be a small fare increase (for example, due to new flights being at a weekend and not midweek).
With no change fares, the cost of changing a return once travel has begun should often be nothing and occasionally a small difference, and very occasionally a lot (if your ticket has to change from I to J, for example).