I don't like to push lawns in the spring even if they've been neglected in the past. I don't know if I'd even try to explain to the customer the reasons why it won't turn around over night unless they bring up a results issue before you start or during the season. After all you should see some progress no matter what. Problem will only occur if customer expectations don't mesh with reality. That will usually show in pre sale discusssion. In any case sell down results and anything better will then beat their expectations. I know your a few weeks ahead of us and although familiar with the area don't know about the timing. Un educated statement is the first 2 could be bumped a week or 2 later but I'm not sure. Ask locally. I sell grub and fungicide treatment only if a problem is diagnosed AND treatment is justified. If the problem is iffy, I explain my on the fence attitude and let the customer decide. I only blankey one app of surface feeding insect control in mid summer and that seems to be the usual around here.