when should i pre-populate my cache tho

Hey everyone, I'm looking into caching strategies for a project I'm starting soon. I'm not totally sure when it's best to pre-populate a cache, though. My first idea is that it's great for situations with lots of reads and few writes, especially when initial load times are super important. But, I feel like I might be missing some downsides. What do you all think about when pre-population makes sense compared to just letting the cache fill up as needed? I'd love to hear about your experiences!