Does anyone know how long relaxer will last before it goes bad? I'm going to self-relax again now that I feel I'm better educated. I was going to get one of those big 4lb tubs of Mizani since that's the only size I can find it in. But if I'm going to touch up every 8 weeks, I'm thinking that tub could last almost 2-3 years. But I'm wondering if it would spoil or loose some of it's "umph" by then. I called the company I was gonna' buy it from and asked if it had an expiration date on it, bu they said it didint'. Anyone know? Or know where I can find a smaller application of Mizani?