I have to get a bid in to a large company here in town, with 600 feet of chain link fence. It needs to either be sprayed or trimmed. I would prefer to spray it (I cant do it myself but have a sub all set up to do it). My question is how often should I plan to spray it? I know this depends on how fast the grass grows, etc., but is there a basic schedule you guys go by? every 6 wks. is what I figured, but I'd like to see what you guys have to say.