Blueberries don't need repotting very often. Not nearly as often as fruit trees or figs. You basically only need to repot if the vigor drops below acceptable levels. I had one plant that I repotted after 7 yrs but it really didn't need it. You can always pull the plant out and see if there are circling roots. Mine had little to none at 7 yrs.

Only time I've needed to repot is when the media broke down and became water logged. Those plants are usually better discarded because they're very hard to get growing again.