In the publishing world, writers typically charge by the word. You set a rate, the client sets the article length and you just multiply to get your fee.

A flat fee equals simple invoicing and avoids the hassle of time-tracking. But when you step outside that realm, you mainly charge by the hour. Hourly rates are difficult to establish and even more so to track.

Here’s what I mean. Recently, I did some editing for a client I estimated would take four hours. However, the client came back with edits requiring an additional two. When I sent in my invoice, I made the rookie mistake of plugging in the six total hours without further explanation. The client sent me a query and when I explained the discrepancy, she understood. However, I’ve since learned to be more detailed in my invoicing.

Many accounting programs let you track time spent on projects and note that information on an invoice. But when you’re juggling multiple projects, going in and out of a program like that could be taxing.

A consultant friend recommends the notepad-and-stopwatch method. Whenever you begin a task, make a quick note of the start and click off the stopwatch when you’re through. (She says it seems invasive at first, but you get used to it.) At the end of the day, go into your time-tracking program –which could be something as simple as an Excel spreadsheet – and mark down your times.

Most consultants I asked said providing total hours for each day worked provides enough detail for most clients. Several colleagues recommended asking your hourly clients how they prefer to be invoiced and noting that in your customer contact information.

I also find it helpful to keep all e-mail attached to a project clustered. In my example, when the client queried me, I was able to paste in her message requesting those edits so she could see the extent of her changes. Remember, clients are working with a bunch of contractors at once so they might not remember every interaction. Keeping a virtual paper trail is critical.

If you forget to note the time and dates you spent on a project, you can use the time stamps on your documents as an aid to figuring it out. Document programs provide at least the date the file originated and was last modified. However, don’t rely on this as a solid time-tracking method.