It depends. On company culture, your manager, and your role, among other things. If you're doing a huge career change, side projects may be your only way. But

It depends. On company culture, your manager, and your role, among other things. If you're doing a huge career change, side projects may be your only way. But most companies (in my experience at least) recognize the value in having their application developers understand some Ops work, and vise versa. Many (most?) companies won't entirely "firewall" you from other groups. Even if you're throwing an application over the wall to ops, there's usually opportunities to learn from them, help out on specific tasks, etc. That said, learning at work is probably _better_, but I do think side projects with a specific goal (e.g. to learn a technology) are a valuable supplement.