What are you waiting for?
Sloppy, ambiguous or unclear contracts and specifications nearly always end up coming back to bite you in the proverbial behind. You would be amazed how often this happens.
When authoring a contract, spend some extra time covering all your bases and scenarios. This way you don't get caught in a situation you should have envisaged but did not because you were lazy or in too much of a hurry. Nowadays it seems people's language skills have degenerated with the use of too many acronyms, emoticons and other forms of shortening or misspelling words. This can only lead to more problems in agreements.
State your requirement clearly using generic language that everyone understands and if you need to use acronyms or "organisational" language, add a glossary clearly describing the meaning.
Similar issues apply to specifications for projects. For example if you describe a deliverable as the supply and installation of an HVAC (air-conditioning) system, be clear as to what that entails. There might not be utilities (water and power) close by. Should installation include routing utilities to the new system or not. If you forget this item, you can bet your bottom dollar the supplier is going to add on a charge when the time comes - an unforeseen extra cost.
So - take the time to think everything thing through carefully and go through your contracts and specifications multiple times before submitting them to a third party. This will save you not only frustration later on but also time and money.