It seems every different agency I work for has different rules on invoicing - some like the contractor to invoice per calendar month ie 1st Jan to 31st Jan), whereas others like us to invoice up to and including last Friday of calendar month (so based on weeks).

I would much rather invoice on a calendar month, as it's pretty easy to remember where you invoiced up to last month. On a 'weekly' type system, always have to check the previous invoice, and make sure there is no overlap. Argh! Come on agencies, contractors are providing YOU with our services, not the other way around! You're making a cut on everything we invoice, and all you have to do is sort the inital contract and interview, and get me my money each month. If the IT industry in London wasn't so fixated on using agencies, there would be no cut for the agency, so how about you accept invoices in whatever format the contrator prefers huh?

(wow... first rant i've posted for ages!)