you'll have to do trial and error, depends what you will be carrying, plus all the tools you'll find out you need after. One thing for me, I sure don't want that bag to be too heavy, I'd rather go back to the shop or out to the van for more. I got a kit for a gift once, had the one for the 5 gal. pail, large satchel, and a small bag with compartments. I mainly only use the small bag. Also, some set up a bag for each job, electric, plumb, carpentry, etc. Me, personally, I don't like the satchel, everything gets mixed together and you spend lot of time trying to find one tool.