I handle the potential slow pay issue with new clients quite easily - the full estimate amount must be in an escrow account if the client has no payment history with my company. I'm talking amounts beyond $5K - a $400 repair isn't worth the effort. On some repairs with fixed income retirees I will offer a payment plan to help them out a bit however if they miss one payment the balance must be paid in full. So far it has worked well. Got burned once on a $65K install job where I got stiffed on the last $12K which equalled my profit margin. So now anything over $5K with a new customer = escrow account to ensure full payment. On repairs I attempt to estimate as closely as possible using a T&M formula - it is here that I have been seeing slow paying. So far I have been burned for about $1600 on one repair. But what really burns my ass is the tax code change wherein loss of revenue due to lack of payment is not considered an allowable deduction. The only time I have really become aggravated was on this one repair - so I implemented an essentially untraceable "revenge". Dude never could figure out why his turf crapped out. Only time in twenty years I did this. Right now all of my maintenance accounts are on constant billing cycles so unless I get a brand new client I get paid in full now.