Whenever I look online for information relating to anode rods in a water heater, they most often say they should be replaced regularly (4-5 years). However, every single plumber I have talked to has told me that they rarely replace the anode rods or they don't at all and I shouldn't worry about it.
So what's the deal? Is it important to replace the anode rods?
What brought this to my attention is that my hot water tastes very metallic but the cold water doesn't. I have a well, water softener, and a particulate filter system (three, 20" filters). The water heater had a lot of sediment when I recently emptied it and I have been noticing certain copper pipes have a lot of green corrosion in some spots. The water heater is 12 years old.