How long to let Fine Fabric Age?

I received my fabric indulgence from Fabric.com yesterday. I have already cut out one piece and the other cotton knit has been pre-washed and is awaiting pattern selection. My Hunny posed the question "You're not going to let that age for awhile?" It's true...I have pieces of fabric that I have probably toted around for 20 years...waiting for the the inspiration. I have the most adorable knit print with brightly colored animals that will undoubtably make my granddaughter the cutest outfit. That fabric has been in my stash since I bought it to make my darling 26 year old daughter the cutest outfit when she was like...3 years old. The outfit never got made, but I can't bear to part with the fabric because I still love it. I have the bag of scraps animal/flower cotton prints from the "Hammer pants" era (remember those Sara?) that are destined to be a baby quilt one day. It was the cutest series, with tiger/lilies, snap/dragons, dog/woods, pussy/willows and dandy/lions to name a few of the combinations. I bought yardage of all of them and most were made into clothes for Sara, when Mom couture was still acceptable. Then came the covert thrift shopping missions, or how I deceived my child, but I will leave it at that...Sara can guest blog about that sometime. It's like some pieces of fabric are just sitting there, aging like fine wine...waiting for their time to come. So tell me...how do you age your fabric?