Well I need to do gross exemption as a contractor, for starters (that bit I'm all right with), where I've realised it gets complicated is when you start to look through the lists of what is, and isn't, covered by the scheme. For example, electrical power systems INSIDE a building are covered, but not those outside - so laying an SWA across ground isn't included, nor is fitting external lighting. Nor is design time (that counts as professional fees), nor is fitting of IT systems (so discount the CAT5 runs), nor is alarms and safety systems....... it's a STUPID system if you ask me, which is why I've always found a work around before when it's mattered. And all because builders' don't pay their taxes.