If you haven't done it yet, it's that time of year to be doing leaf analysis for citrus and avocados. Analysis prevents deficiency symptoms from appearing and maintains good yields, all else being well done. To get an idea of what extreme situations look like, take a look at look at these symptoms on various webpages. The one from UC IPM, also includes other leaf symptoms besides nutritional ones - disease, pest and abiotic.
UC IPM
University of Florida
https://edis.ifas.ufl.edu/publication/CH142
Haifa Group
https://www.haifa-group.com/citrus-tree-fertilizer/crop-guide-citrus-plant-nutrition
A brief explanation of leaf analysis: https://ucanr.edu/blogs/blogcore/postdetail.cfm?postnum=28217
Citrus leaf potassium deficiency. You don't want to see this, and is one reason for leaf analysis.
