It is incredible that you have been wearing monthly lenses for over a year! 30 day contact lenses are also called extended contacts which you can wear non-stop for 30 days. It is made of special lens material which contains silicone, making them more permeable to oxygen, allowing your eyes to 'breathe' better. They are quite convenient for people who don't want to take off their contacts everyday. But you should better take them off every week and clean them.
30-day contact lenses are also called continuous wear lenses that are approved by the FDA for up to 30 consecutive days of continuous day-and-night wear without removal. It is designed to help you to solve the problem that you do not want to wear eyeglasses and also are afraid of doing surgery. Generally speaking, it is safe, however it is also kind of risky. Wearing contact while sleeping may cause eye infection and wearing them for a long time may increase the risk of dry eye and visual disturbances. 30-day contacts can produce excellent vision quality but the problem is what happens if your vision changes over time.
The 30 day contact lenses are also known as extended wear lenses, which is made of soft contact lenses for wearing 30 continuous day-and-nights without removal. With this kind of contact lenses, you wouldn't feel uncomfortable without removal for several day-and-nights unless you have sensitive eyes. However, you had better clean them every day to avoid thick dust on them. And compared with other period contact lenses, it is just slightly expensive than others.
"I've been wearing monthly lenses for over a year now." does this mean you've been wearing one pair of monthly contacts for over a year or in over a year you've being wearing monthly lenses (change every month)? If it is the former, I strongly suggest you do not let them in your eyes again. It is very bad for you as the overdue contact lenses have worse oxygen permeability, and this makes your eyes easy to infect. 30 day contact lenses are the kind of contacts should be threw them in 30 days after you wear them from the first time, the same as monthly lenses. If you don't wear them often, you can have them more than one week, but never too long. The badness I present above, right?
The 30 day contact lenses are the kind of contact lenses that can only be used for a month. More and more people are choosing to buy them. Because they're convenient and concise than the yearly contact lenses. Many people who just start to wear contacts also pick the 30 day contact lenses for practice. They are almost the same with other contacts in function. Therefore, wearing monthly contact lenses would do no harm to your eyes as long as you have developed a good habit of cleaning them.