First you want to understand that the name of the game when recording for your client is keeping your client happy. And when your client is paying a pretty penny for studio time, the faster your Pro-tools session is up in running and ready for recording, the less time the client is standing around waiting on you.
The second advantage to using a well laid out template is clients usually like to have a rough mix to reference, and they like to have it sooner rather than later. Well, with a well laid out template, it should only take about five minutes to quickly put one together. If you can let a client hear a rough mix before they leave the studio that day, it will really make them happy. Clients like to know that they are not going to have to rebook more studio time to rerecord a song. So having a rough mix ready for them before they leave the studio helps everyone feel more comfortable that the just recorded songs are recorded well enough that the right tweaking will lead to the professional sound they are looking for.
One more thing that I like about using a template that I am familiar with is this: It lets me make adjustments on the fly. Having plug-ins that I know I am going to use already plugged in when someone is recording can help me sometimes make microphone adjustments and level adjustments right on the spot. This helps me come out with a better recorded sound, which makes the mix process easier.
I suggest making more than one template. Think about what you record the most and make templates for those types of music. If you mostly record rock, pop and hip-hop, make a template for each one. Make sure your template has all of your basic plug-ins that you are going to use. And ensure that each track, including MIDI, AUX and instrumental tracks, are routed to the proper places and everything is labeled.
When it comes to setting up your template, you should always use this rule of thumb: You never can add too much. Anything that you know you will have to add later, add it now. For instance, let's say the last time you recoded a rock band, they used 25 tracks, but this next band you are going to record will only need about half of those tracks. When you load up your template, you will have double the tracks, but this does not matter. You just don't record on those tracks, and if it makes you feel better, you can just delete them when you get a chance. The process of deleting a track is as easy as hitting a button; the process of adding a track is much more time consuming.
Even though templates may take a while to set up, and in most cases you will probably find yourself changing them around a little bit until you find the ones that really work for you, it will still save you time in the long run. So put a couple of templates together and carry them with you to every studio that you go and record at, trust me you will not regret it.
TIP: I used Pro-tools as an example but you can make templates for whatever program you use so take advantage.