To find out whether you need to run balance, just have a close look at the output of
sudo btrfs filesystem usage /path
Overall:
Device size: 476.44GiB
Device allocated: 252.04GiB
Device unallocated: 224.40GiB
Device missing: 0.00B
Used: 224.00GiB
Free (estimated): 250.86GiB
And compare the difference between "unallocated" and "free", and "allocated" and "used". Snapshots can play a big part in this.
The higher the difference, the more it is likely that a balance operation can help.
You should not run a full balance, since it will rewrite almost everything, potentially leading to SSD degradation. A factor of 50% might be a good starting point.
EDIT: after a balance of 60% on the above, I get this:
Overall:
Device size: 476.44GiB
Device allocated: 245.04GiB
Device unallocated: 231.40GiB
Used: 223.99GiB
Free (estimated): 251.86GiB
Notice the difference.