I've been brewing for about 18 months. From each batch I have put away a few to sample at 1 year or later. So far it has been a mixed bag. My first beer a Red Ale and my Brown Hoppy both tasted fairly oxidized, however a couple of stouts I did were better than ever. Hops flavors really decline with age which makes those wonderful IPAs and Pale Ales very different. However the changes to stouts and porters is much more subtle and I think beneficial.