This is subject is how I found this forum.
I have been doing carpentry for over 20 years. I have always had trucks with toolboxes. Now all trucks have utility beds. I started re-evaluating how I was doing business. I purchased 2 trailers. 1 - 7'6" x 14' and 1 - 8' x 18' (i was looking for a 16', but when you buy used you don't get alot of choices)
The majority of our jobs last from 2 weeks to 2 months. If you figure up how much time you spend loading and unloading tools, you will be amazed at how much time you spend not making money. Not to mention the times you need a tool you either forgot to load or ended up needing.
We still have the utuilty trucks with enough tools to do most things. (Old habits die hard) We leave the trailers on the job. This can be a risk. We just take the best precautions we can to secure the trailer. A the end of the day we can throw everything in the trailer pretty quick. The next morning we don't have to load anything up because it is already on the job.
For us, trailers have increased our productivity by having everything we need, on site.
Hauling a trailer around, especially the 18', is not that convenient. Also if we leave the trailer hooked to the truck we will have to unhitch if we need to run get materials.
We use the 14' trailer for concrete tools. When we show up we have everything we need. It has worked out great.
The truck maintenance is another aspect. I have had times when my work truck is in the shop for over a week. One truck had to have the transmission replaced twice. During those times it probably would have been easier to take a vacation than try to work out of my personal truck.
Now with our trailer, if a work truck goes in for service, I can drive my personal vehicle to the job and all the tools I need are there. I can also pull the trailer with my personal truck.
Sorry for such a long post. I have put alot of thought into this subject and could go on about the pros and cons for pages.