how accurate are expiration dates?

So i decided to go through the fridge today and found some things that had expired.  i'm not sure if some of them are guidelines or what, so if anyone knows it would be very helpful for me!!  okay so here are the items (i live on my own so its hard for me to eat everything in time!)

i cant believe its not butter: feb 2 '09

kozy shack tapioca (refridgerated): apr 15 '09

sour cream: feb 24 '09

cottage cheese:  mar 28 '09

hotdogs: apr 20 '09

carrot relish:  feb '09

any of these still okay to eat, or should i throw it all out?  thanks!

Frankly, the expiration date is meaningless once it is opened.  Definitely, throw it if it smells or looks "off".  I've had things in the fridge beyond their expiration date, even opened, and they were fine.  Other things expired before the date stamp.  Sour cream and cottage cheese are probably the hardest to tell if it has expired, though, because they already taste and smell "sour".   The hot dogs are probably still okay, just cook thoroughly before eating, and soon.

I like to live on the edge so I don't pay too much attention to the expiry dates.  If there is mould on something (other than cheese - I just cut it off, I know, it still has 'invisible' mould way inside, but I'm ok with that..) I don't eat it, but if it looks and smells fine, I do eat it.  For the future, you could just freeze the hotdogs and probably the margarine.

Also, are these things still sealed, or have they been opened?  If it has been opened, I would be surprised if the cottage cheese and sour cream still taste/look/smell good. 

My rationale for eating expired foods?  An elevator whose posted capacity is 1000 lbs can actually hold way way more than that - things are built with a 'cushion'.  I'm assuming (I don't actually know, and have only my own continued health to back up my assumption) that expiry dates have the same kind of wiggle room built in.  (I think maximum dosages for cough syrup and advil etc... have a cushion built in as well).

Flybe is right, there is usually a bit of lee way on the exiration date, dry,canned or frozen foods may be fine months after the expirery date. In the UK we have Use by and expirery dates, generally fresh food hase a use by like dairy,meat and veg.

unopened vacume sealed food will usually be fine a week after expirery unless its raw meat.

Dairy such as soft cheese and milk dont use after a few days of the expirery because they go off quick and might make you ill, definatly throw the dairy away because 1-2months is FAR too long.

If the hotdogs/tapioca are canned then they should still be fine, if they are fresh then throw them away as there could be all kinds of bacteria on the meat and dairy, you really do not want to be eating fresh food that has been sat in liquid and exposed to the open air for weeks.

In your case i'd say throw everything thats been opened because they are all weeks/months old.

You must have an imaculate house because if i left any open food in my fridge for more than a week or two it would defenatly be mouldy!

In your case I definitely agree...chuck it all. Especially, the dairy (without even opening the container)!

For the future if you want to read up about it CBS News did an interesting story on expiration dates.
http://www.cbsnews.com/stories/2009/04/18/ear lyshow/health/main4953898.shtml