There are many views on upgrading…. I will share with you my general approach (Synology, Android, etc...)
I currently still don't own a pfSense box ??? :D
Assuming it's only for home use, you don't have big secrets to protect, pfSense is not your full time hobby, you are not an active pfsense user in the community, you don't have a job in network routing domain and you don't want to spend too much time updating a router box.
Below is my order (1st being the highest priority)
ASAP if there is a major exploits or vulnerabilities that is trending online (e.g. Read on Apache struts)
pfSense released a patch version that fixes a bug affecting you directly (feature) or indirectly (performance, high cpu or memory leaks)
When pfSense release a minor version you really require (feature, performance)
When your version is no longer supported, might be time to upgrade (if time permits)
Major version changes, hardware supports it, it's time to upgrade to keep up (if time permits)