When should you switch from SQL to NoSQL?

i've been thinking a lot about data stores lately. we're all-in on relational databases for everything right now, and honestly, they've worked great for us for years. but as we scale up and our data models get more varied, i'm starting to wonder when the advantages of NoSQL databases (like document or key-value stores) will start to beat out the familiarity and ACID guarantees of SQL. has anyone gone through this? what made you switch, and what were the biggest surprises or hurdles you ran into? i'm really curious about cases where NoSQL actually fixed something that SQL just couldn't handle easily.