I sew very, VERY thick fabric together when making my concealed carry handbags. I thought my heavy duty sewing machine would be able to handle the work. However, it really does not do as good of job as I would like. I have just been using the standard foot that came with my machine. Come to find out, I should have been using a walking foot.
I've heard about the walking foot and considered purchasing one, but I did not realize that with my machine it is a necessity if you are sewing very thick fabric. Walking feet are pretty pricey, so I guess that always scared me off.