Partial / mini mashes are a good way to get an idea of the time and effort between an all extract brew and all grain. It'll add about an hour to your brew day, maybe even a little more, because you end up performing the mash of an hour and sparge the grain at the end. I only did one partial / mini mash kit before going all-grain BIAB. The process of the partial / mash answered many of the lingering questions I had, and it made a ran good beer!