Business-focused custom software

Even if you aren't paying for custom software on an hourly basis, you probably still care about how long it will take for the programmer to complete the work. After all, you hire a programmer because you think custom software will add to your bottom line, either by saving you money or increasing your marketshare. So every day without your new software is costing you cash.

Programmers are notorious for missing deadlines and taking longer than they promised. So if programmer says they will be done with your project by X date, how can you tell if they are just blowing smoke or if they really know?

Sync your terms. Sometimes the problem is really a question of interpretation. The programmer says "I'll be done on June 1st", and you think "Cool - we can start using it then!" But really, the programmer just meant the initial code would be done on that date, and wasn't referring to set-up, testing, deployment, or training - all additional tasks that must be completed. So, when you talk with the programmer about milestone dates and deadlines, make sure you are speaking the same language. Ask specifically about when you'll be able to use the software "live" or "in production".

Pay attention to the trees. Don't just focus on the "forest" or end goal. A good programmer knows that there are a lot of intermediary steps that occur in any software project. They should be able to provide you details and estimated completion dates for each step in the process. You want this for two reasons. First, there may be tasks for you or your staff to complete in this process, such as testing or entering products for an online catalog. You may learn that the programmer will be fine, but you'll need an additional week to complete your tasks. Second, uses this opportunity to probe further. You may not know anything about programming, but you probably have some sense of what is going to be complex. Ask questions about the details you have received to make sure you understand what to expect. A good programmer will welcome the opportunity to double check their understanding of the requirements with you.

Ask their references. When you talk to their references (you are checking them, right?) make sure to ask about how well they did with the deadlines. Some programmers aren't good at estimates, and others aren't experienced. 

Estimates are always tricky, and don't expect the developer you select to be perfect every time. But you can expect that they will work hard to meet the commitments they have made to you, and will let you know if they can't.