I'm starting a business with a partner and we're 50 / 50 partners in responsibilities, funding, and ownership

We would like to take advantage of the tax benefits of deducting business expenses

For some items (e.g., vehicles, meals, etc.) this feels trickier to do with a 50 / 50 partner than it would if you're a solo owner because the expenses won't be equal. For example, the car owner A wants to buy is different than the car owner B wants to buy.

Part of a healthy partnership seems to be a mutual understanding that it will never be perfectly 50 / 50

But we're curious how have others approached this?

On a similar note, we'd love to learn best practices on how to maintain clean books so that it's easier to justify EBITDA if we decide to sell.

Thanks!