The pitter-patter of rain drops on a car's window can be a distraction. This is compounded by the fact that some people want fresh air to flow in during a rainstorm, but cannot do so in the event of a downpour. This is solved by the introduction of vent visors into a car. Vent visor provide cover to a partly open window during a downpour, making sure that people can get fresh air inside even while it rains. However, vent visors do also deal with issues such as these:
Some vent visors are made and marketed as 'in channel' visors which are meant to fit into the groove of a window. However, these visors are also notorious for being in the way every time you close your windows. When closing up, they tend to get stuck and have to be pushed with a finger in order for you to keep on closing your window. The problem, it seems, lies with the double-sided adhesive that does not cover everything.
Some of these visors do not work so well in different situations. Some of them, after installation of some time, tend to show signs of wear and tear. The usual hint of this is a tell-tale crack in the corners. This is never good for any visor, especially since they are trusted to keep the water out, not let the water seep through the cracks. This is due to the fact that some visors do react poorly to different weather than other visors, resulting in the cracks that you notice in corners.
While there are no problems whatsoever with your vent visors when they are put on, these may show up when changing your vent visor. Vent visors tend to be a messy lot when they are about to be changed with new ones. Mainly, the problems you meet when changing vent visors are the dirt and stains from the tape line. Since it is exposed to rain and different conditions, there are many contaminants that may get stuck in the adhesive.
There are many other things which you may find as a problem with your vent visor. Figure out if your vent visors are correct for your windows before trying to fit them. Learn to check for loose adhesive as well, if you want to keep your vent visor stuck on your car.