The contact lenses are divided into several types according to the using time, such as the daily disposable ones, monthly ones, half-year ones and yearly ones. If your colored contact lenses don't belong to the daily used one, you could use it again within the expired time. However, you should keep the good habit of hygiene.
Well, it seems that you are interested in colored contact lenses, yes of course, they are amazing and could make you appear much more attractive. So, actually, every pair of contact lenses has got a period of duration such as daily, monthly etc. So, how long you can use the contact lenses depends on what type of contact lenses you choose. If you choose daily colored contact lenses, you shall not use it again.
It depends what kind of colored contact lenses you wear, if you have disposable contact lenses that is used for one day only, you have to throw them away using once. If you have cosmetic colored contact lenses, you had better not wear them more than once if it is unnecessary.Due to the color would be brighter than the normal ones to highliten the effects, and they are directly touch your retina. On the other side, if you have corrective colored contact lenses, you can wear them for a certain period, but you have to take them off and clean them in the night.