How can these big co's Trugreen, lawn doctor etc. keep selling repeated applications of lime and grub control? Once your Ph level is where it needs to be, everything i have read says it should be fine for 3-5 years? Grub control every year? found an old post on milky spore building up a resistance, to use nematodes instead. Either way i know the're making more money by repeating apps. every year but aren't they blatantly ripping people off?