Storing your remedies the correct way will keep them potent and active for a long time. Store the remedy in a cool, dark place away from heat, light, electronics and strong smelling substances (think perfume, peppermint, strong herbs etc).
Over time, things like airline scanners or being right beside your cellphone in your handbag can weaken remedies. If you travel a lot or tend to keep remedies in your bag, just be aware they might not be as active after a while as the ones you have in the bathroom cupboard. It's always useful to have a kit in your bag and a bigger bottle in the cupboard to refill your kit remedies when they get low or if they have been exposed to anything that might have weakened the remedies.