So, I am about to order my boil kettle and mash tun. I plan to be doing 5 gallon batches, not that 10 won't be out of the question. I also want the ability to do "big beers". I really don't know if I will ever switch to 10 gallon batches, but it's not outside of the realm of possibilities. The cost difference between the 15 and 20 gallon isn't really a big deal. So, that being the case, what are the advantages/disadvantages for going with 20 gallon kettles vs 15 gallon? What would you do in this case? I would really appreciate advice from those that have used 20 gallon kettles to brew 5 gallon batches in an electric setup and any that have done 10 gallon in 15 gallon setups.