I sell my services by the day. I don't screw around with hours. If I work ten hours, that's fine with me. If I work 6 hours, that's fine too. After all, I'm usually hundreds if not thousands of miles away from my family. If I'm there, all I am doing is working and thinking about you and your problems. If I'm not there, I'm not.
I was very happy when I went to the day system. I know guys that worry over coming in five minutes late and spend much time each week creating very detailed reports that nobody cares about. I figure if I'm worrying about five minutes or filling out a TPS, I'm not working on the big problems like you are expecting me to. I'm not working in your best interests. The simple thing is either you trust me or you do not. If you trust me and somehow feel I owe you some time, we'll work it out. If you don't trust me, we shouldn't be working together. We got bigger problems than whether I wasted an hour 18 days ago trying to figure out how to use your help desk services.
Admittedly it's much easier to be this way after consulting for many years. If I were a junior or entry-level consultant, or worked for a large shop in one of those fill-the-seat contracts, it'd be a different deal. Thank God I don't do that anymore. Had a gig once where I worked for lawyers and accountants. There was never a week that went by that they didn't have problems and correct me on my project paperwork. As far as I knew, they really liked me. It was just the corporate culture. Damn that was a miserable experience.
Similar here - I've got a 'day rate' for on site visits - they're whole day (usually multi day) affairs. I have hourly as well, for smaller chunks of time, and I'm generally doing those from home. ATM I've still got a number of smaller projects that will never take up a whole day of work at any one time, so hourly fits those, but I'll probably move toward daily rates for more work in the future. It generally keeps me more focused and more productive on that one client's projects than trying to juggle 3-4 things in one day for 1-3 hours at a stretch.
I do the same thing when I have to travel to customers' sites. I don't bill for travel days, and bill a uniform 8 hours a day for onsite.
That said, I live 2.25 hours away from the Phoenix Airport (up in the mountains) and I try very hard to not travel. When I work at home I use desktop timer and keep track to the minute. This is actually a low overhead activity.
A tip: documenting work tasks for invoicing is a high overhead activity. I reduce this overhead by attaching my complete working notes log to my invoices, and nothing else. I need copious notes on my work for technical reasons, and reusing my work notes saves me a lot of effort. I have the occasional client who doesn't like this because it is way too much detail for them, and in that case I charge them for the few minutes a day to write a short summary.
I also sell my services by the day, having screwed around with 'projects' for far too long. You need customer trust in order to do this, and that's often hard won, but until a customer sees your time as valuable, expect them to unload lots of extra unpaid-for work (ie: poorly thought out features) on to you.
I was very happy when I went to the day system. I know guys that worry over coming in five minutes late and spend much time each week creating very detailed reports that nobody cares about. I figure if I'm worrying about five minutes or filling out a TPS, I'm not working on the big problems like you are expecting me to. I'm not working in your best interests. The simple thing is either you trust me or you do not. If you trust me and somehow feel I owe you some time, we'll work it out. If you don't trust me, we shouldn't be working together. We got bigger problems than whether I wasted an hour 18 days ago trying to figure out how to use your help desk services.
Admittedly it's much easier to be this way after consulting for many years. If I were a junior or entry-level consultant, or worked for a large shop in one of those fill-the-seat contracts, it'd be a different deal. Thank God I don't do that anymore. Had a gig once where I worked for lawyers and accountants. There was never a week that went by that they didn't have problems and correct me on my project paperwork. As far as I knew, they really liked me. It was just the corporate culture. Damn that was a miserable experience.