Young people especially young girls like colored contact lenses as they can enlarge and color eyes. There are several notices of wearing colored contact lenses. First of all, contact lenses have different service life. Some are one-off and some can be used for one month or one year. Use them in strict accordance with the service life. Never reuse colored contact lenses which are not reusable; otherwise it may make terrible damage. Additionally, as colored lenses contain more chemical additions than common lenses, it means more care should be taken while wearing. Don't wear it every day and wear it no more than 8 hours one day.
If the colored contact lenses are out of the used date, you should not reuse them again for the no effect for you eyes to breathe the oxygen again. You'd better buy the new one. And if it is still within the used date, you can use it. But keep the good habit of hygiene and change the solution often.
Well, in fact, there are a lot of reusable contact lense with colors. Generally speaking, their duration differ from one another, some is half a year, some is three months, it all depends. As to the safety, I gotta say, it is unknown. Because it is reported that some people get infected eyes due to a lack of proper use and cleaning. So, you have to pay a lot of attention if you want to wear them.