The worst thing that has happened when I leave beer in the big plastic bucket for more than six weeks is that the final product tastes "yeastier". And that's only for the lighter recipes. I had an oatmeal stout that sat on the trub for four months, and was outstanding. Granted, I had the barest hint of a sherry note on it from some oxidation, but that ended up complimenting the roastiness pretty well. Wouldn't have been a problem in a glass vessel. If it were something super-light like a Kolsch or Blonde, I might would have cold conditioned it to settle some of the yeast back out.