Although they're are very inexpensive to make from scratch as needed, I'd like to have a small storage of agarose gels for experiments (e.g. checking clone inserts, plasmid sizes, usual stuff).

 

What's the best method to store them? I usually make 1% agarose gels with ethidium bromide. How long do they stay fresh, without impairing the quality of the results?

Not too long, if you really want to have good analyses. If stored it will probably be good for maybe a week, but usually you will note gradual decline in quality. Moreover, you have to store it away from light, if you use EtBr. As agarose gel can be made so quickly it usually does not pay off to make a large stash of it.