Q.Pruning
Live in southern calif. Have a grapefruit tree over 100 yrs old produces fruit year round. But I have so many leaves that they block the sun to the lower limbs of tree. Should I cut the leaves away if so when is best time since fruit is constant on tree?

Certified GKH Gardening Expert
Research says not to prune grapefruit trees because disease could set in. Since your tree is so old, I would contact your local Cooperative Extension Service or an arborist before doing any trimming.
For other citrus trees, it is recommended to remove diseased, damaged or dead branches and to thin the canopy if needed to let light in. However, I would consult a tree expert before even doing that on a tree so old.
Here is general pruning information:
https://ucanr.edu/sites/Tuolumne_County_Master_Gardeners/files/160549.pdf