If you do it right and don't oxidize it or expose it to light (espeically if its in green or clear bottles) then it will keep for months.. maybe even a year or more. I've been very busy at school recently and have had to dig into my stash, unfortunately I just finished one of my first all grain batches - it was about 9 months old at tasted absolutely great... it got better every month it sat in the bottles. Point is, homebrew will benefit greatly from aging. Darker beers especially mellow out and blend with time. One thing that does degrade however is hop aroma and bitterness.. this is not a huge problem (your beer won't taste awful) but you may notice that the hop nose on the beer is disappearing after a while.
The problem with homebrew is not that it goes bad.. the problem is managing to not drink it before it gets really really good!
As for what you need for a basic extract setup here's a list:
-primary: if you can afford it, do it right and go with a glass carboy and not a plastic bucket
-secondary: let your beer age in bulk, clear, and give you to opportunity to dry hop it. You definitely need a glass carboy for a secondary.
-large kettle: For extract batches you'll probably be doing partial boils (concentrated wort) and so a 5 gallon pot will be sufficient. You can do a search on this, it's been beaten to death, but aluminum is absolutely fine. Stainless would be ideal and ceramic coated work well too though they're fragile and ruin if you chip them. A full volume boil is better than a partial boil and you can do this with a turkey fryer. For what you'd pay for a large kettle you could get a turkey fryer for $40 that comes with a propane burner AND a large (i.e. 7.5 gallon) kettle. It'll allow you to do full volume boils, you can do it out side where the wife can't complain about the mess in the kitchen, boilovers end up on the ground instead of on/in the stove, and you have a vital piece of equipment should you ever decide to go all grain.
-siphoning system: a racking cane is a PITA! An autosiphon is a great $10 investment but I think an even cooler and simpler (though still cheap) setup is to use those carboy caps.. do a search on this one and you'll see what I mean.
-hydrometer: yes, some people go without.. let's not go there please. It'll allow you to check on your fermentation and see how its coming. Plus it'll tell you your abv.
-thermometer: the more of these you have the better. The kind you stick on your carboys are handy (2.50 a piece - you'll want 2) and a good digital thermometer (not the kind with the wire probe - do a search).
-wort chiller: if you do concentrated batches then you can use a sink full of ice. The simplest chiller option is an immersion chiller, you can easily build one yourself - do a search. You'll want a chiller if you do full volume boils.
-tubing: 5 feet or so to allow you to transfer your beer. Change it out periodically since its hard to clean. Don't worry, it's cheap.
-bottling wand: you'll need it to bottle your beer.
-bottling bucket: you'll need it to bottle your beer.
-bottles: 50 is about how many you'll need for a 5 gallon batch
-caps: duh!
-capper: wing capper is cheapest and works ok even on narrow necked european bottles (do a search) but a bench capper is nice.
-sanitizer: another pandora's box (do a search) please save yourself the grief of using bleach as a sanitizer. Get some star san.. it'll last forever.
-carboy brush: to clean the gunk out of the carboys
-airlocks & drilled stoppers: to seal your carboy.
-priming sugar: to carbonate your beer. It's corn sugar.. cheap and effective. Malt extract seems to take longer and, in my experience, doesn't make much difference. Don't use table sugar.
-turkey baster: to remove beer from the carboy for sampling... you could just siphon it out but that can be messy sometimes.
-bar keepers friend and unscented bleach are great cleaning agents.
-a water filter if your tap water tastes terrible
I think that's probably just about everything. Obviously, somethings (hydrometer, turkeybaster, bench capper, turkey fryer, wort chiller, etc.) are luxury items but they are still very very helpful. I wouldn't recommend something that is useless. Eventually you'll probably come to own everything on this list and more. You should definitely read Palmers "how to brew" - it's free online:
www.howtobrew.com.
It's a really great resource. Happy brewing!
