I am a fan of mixing functional and object oriented (and also some other paradigms). Functional is great in cutting amount of repeatable code. It is great for

I am a fan of mixing functional and object oriented (and also some other paradigms). Functional is great in cutting amount of repeatable code. It is great for writing tools to process things regardless of their exact type and for writing infrastructure code. Object orientation is great when you want to model the domain of the problem. Things that actually make sense when you are talking to non-developers at your company. Clients, contracts, appointments, employees, teams, invoices, things like that. But when you start making objects that do not represent anything meaningful you probably went a bit too far. I think knowing various paradigms, knowing when to use which and how to marry them together is critical for maintainable implementations.