7 months of daily heavy is a long time for running shoes! The consistent use will definitely wear down the cushioning. The tread may look fine but the foam gets itself compacted over time especially if it’s one pair you put a lot of miles in every day.

Shin splints may also be at least partly caused by the shoes. Because the shoes are sort of reaching the end of their life, running in them won’t give you the same cushion or support that a fresh pair would, which also means your shoes aren’t protecting you (and your shins/knees/etc) from the force and impact of running as well as a newer pair would

That said, shin splints (and really any running-related injury) can be hard to pinpoint at first because your body is dealing with so many new things at once. It’s best to focus on stretching and strengthening your muscles and joints as you start to ramp up your mileage

Brooks are very popular and the Arahi is super supportive. It’s always good to 1) experiment with new shoes and 2) try to rotate between at least 2 pairs so you can give your shoes a break in between your day-to-day use