I carry my tablet with me all the time. It used to be the Surface Pro, but I sold it. Too much machine for the field, and that's all I needed it for anymore. So I got a samsung 9,7inch tablet with the S pen. I use it more for sketching when needed or files referencing the project. When Im in a good local, I can give the tablet internet from my phone, and if I need to look something up on the internet I do. If you need to look up info for calcs, you could probably just put it in the tablet and reference it when you want to. Im too much of a noob to re-disign in the field honestly, at least when it comes to non residential projects. Keeps me up at night.....