I'm sure that if you use the same strains, nutes, soil, temps, etc. all the time, that you can get things dialed in to the point that you don't need to know how 'hot' your feedings are. However, what if something changes - e.g. what if you move or switch to a different water supplier? Then you might have previously had 200 ppm in your tap water but now it's 500, and your TDS meter (which, by the way, doesn't have to be a fancy piece of equipment - mine cost about $20) can help you keep your plants happy.
Myself, I'm glad to have an extra check on potential errors - I have been known to lose track of how many teaspoons of nutrients I've added to a watering can, and testing before pouring can save my plants from a needless poisoning!
Myself, I'm glad to have an extra check on potential errors - I have been known to lose track of how many teaspoons of nutrients I've added to a watering can, and testing before pouring can save my plants from a needless poisoning!
