Sounds like you have an excellent arrangement and each of you looks after their own property and takes care of all your related problems. This to me would be an ideal strata situation. Self management is the way to go if each owner maintains their own property themselves.
BUT
Have you formalized this arrangement by creating a Strata document and registering the bylaws you both agree to. The byelaws should state that each owner is responsible for their own property in it’s entirety. Doing this now whilst you are on good terms with your neighbor removes the risk that at a future date they sell and your new neighbors are not so accommodating.