What if you have a very large opening? Say the size of a whole wall in your family room, overlooking a great view? If you are thinking blinds, the mere size of the necessary blind can make manual raising and lowering not feasible. The strings that do all the work can break easily under the weight of the blind. Look for another method of controlling the shade. A couple of options are called Easy Rise and EasyUp. A remote control is another consideration when looking at a large opening, either doors or windows.
Also think of breaking up the space. Rather than one humongous blind, go with a number of identical blinds that are smaller in width. As well as lessening the weight of a pulled blind, you also have more lighting options. Raise the blind on the door you use most often and leave the blinds lowered on the others.
If your windows are high and difficult to reach, you may want to avoid the manual opening and closing altogether. The hanging strings can be annoying and unsightly as well. Look for a blind situation that you can raise and lower by a remote control.
Think about windows around your TV and computer as well. Even a small speck of light coming in through the holes in the blind can cause glare on your viewing or computing pleasure. There are blinds that have eliminated the "route" holes (one such product is called "De-Light") to make sure there is no glare.