Absolutely no need to replace a perfectly good anode rod that has serviceability left.
They are designed to deteriorate......replace when the sacraficial material (aluminum or magnesium) has deteriorated at least 75% gone.

Always a good idea to drain and flush WH yearly to get rid of scale that can accumulate inside tank. A simple inexpensive flushing wand helps.
I turn off water source, relieve pressure on system, remove WH drain plug and then turn water source back on and let it power flush until I stop seeing large chunks of stuff.
Turn water source back off and use the rinsing wand. Another power flush by turning water source on.
Handy little rinsing tool.........
