how do you keep secrets safe in microservices, like passwords and api keys

Hey everyone, I've been thinking a lot about managing secrets lately, especially with our microservice setup. Keeping API keys, database passwords, and other sensitive stuff safe feels like a never-ending fight. Are you folks using a dedicated secrets manager, like HashiCorp Vault, or did you build your own? What worked well and what didn't, in your experience? I'd love to hear about what you've actually seen and any traps to watch out for.