AG products are not issued with a use before or best before date. The only advisory is with trade Fabric Stain Remover and retail Fabric Hood Cleaner and Active Stain Remover which state: For best results, use within twelve months of purchase. This is due to the bio active content (read: dirt eating bugs) of the formula.
Aside from this it is down to common sense really. Would you expect a 20 year old tin of paint to be in a good condition? Answer: maybe. Open it up and have a look, the product may have split due to it being stored way beyond its expected shelf life and 'used-up-by' life or it may still be useable. When polishes and dressings are created, emulsions are usually formed, and it is this element of the product that will fail if anything, and when that is gone no amount of shaking will restore it. Detergents are usually going to be ok; there isn't a lot in them that is going to go wrong when it comes to storage. The only thing to add is that once you open a container and start to use the contents, the preservatives have to work harder as there is more air space to preserve. An unopened container may have a set % of air at the top, and as this increases as air is allowed into the container, more naturally occurring yeasts etc get into the container. This is why a 25L container of shampoo for a guy that washes 2 cars a week may not be the best container size for him.
So what is a reasonable time for a product to be 'out in the wild'? Well, provided people buy pack sizes suited to their usage rate, 2 to 3 years? We know that our products can be made on Monday and easily be on the shelves in Halfords a week later. With that in mind I think a two year use up time is easily achievable. Similarly for your trade user, they are going to be getting through product a lot faster, which is why they buy in 5L and up as they will easily use this in a short period.
This is not to say 'Autoglym products have a 2 year shelf life', as stated at the top, none of our products come with a shelf life, it is all down to considering how long you've had the product in the garage, have you stored it correctly according to any 'avoid freezing' instructions and what is it, a polish or an interior detergent.
