If this is an estimate you're not going to hold me to - a true estimate - then it has certain characteristics:
- You'll get it quickly. This is a gut sense, side of the barn, back of the envelope, breadbox estimate. (Yes, I could keep going with the euphemisms.)
- It'll be a bit vague. "Hours, not days."
- I might not hit it. I'll be close, and I might be over or under, but I won't guarantee it.
If this is an estimate you're going to hold me to, well, that's a whole different story. We've changed the nature of the deal. With this scenario, going over or under is not okay. It's not really an estimate; it's a fixed-fee bid. This kind of estimate has different characteristics:
- It's going to take longer to get it. I have to think about the work and understand it better to be able to identify a time frame that's reasonable.
- It's going to be more precise. "June 15th". I know you're going to be watching the calendar, so you'll probably get a date rather than a duration.
- I'm more likely to hit it. Of course disaster might interfere, but in general these estimates are going to be more padded and I'm going to make the date.
So if you want an estimate, that's completely understandable and legitimate. Figure out, though, whether what you're asking for is an estimate or a guarantee (or as close to a guarantee as possible in this world). If all you need is an estimate, then there's no reason to wait for a guarantee. If you need a guarantee, that's fine, but it's going to take a little longer to get and it's going to sound different than an estimate.
Asking for the one you really need will help make sure no one's surprised later on - and that's a good place to be.