If its any help car batteries seem to fail quite suddenly nowadays rather than tail off gradually as they used to. 5-7 years also seems to be when failures start to occur, so the choice is yours really, change early at your convenience or wait for a sudden failure............like I have had happen on several batteries normally on a cold wet day !
Not keen on jump starting modern cars either as sometimes sensitive expensive electronic modules don't seem to like it.
Halfords own brand batteries came out well in some recent magazine tests and are warranted if you keep the receipt.

 

Mine went on my 53 plate MCS earlier this year, but my battery does have a hard life, as I only use the car at the weekend,