One of the first things to bear in mind is that baby gates for stairs need to be put both at the beginning and at the end of the stairs for you never know which part of the house you will be in. Kidco, Dream Baby, Safety 1st, The First Years, Evenflo and Cardinal are some of the top baby gates makers. There are many models of baby gates available in the market. The important thing is to first measure the breadth of the stairs first. Another important point is to prefer to new baby gates as opposed to second hand ones. If there is no choice but to invest in a second hand one please ensure it is in good working condition.
Think about the kind of baby gates you intend to add to the house. Hardware mounted gates at stairs need to be screwed into the wall frames making it non portable to different parts of the house. Free standing gates are portable but can only be used at the bottom and not the top of the stairs. The doors come in swinging, sliding and rolling door options. If you think you'd like the sliding, ensure that every member of the family does not forget to slid the door back once they pass. If it is the swinging your opting for, install in a manner that the door swings away from the stairs (on the top). The advantage being that the baby will not be able to open the door or that when someone is on their way up, even if the baby tries to slip through, the person walking up the stairs will block the baby's fall. See to it that you buy baby gates for the stairs that have vertical slants and not horizontal so that your baby does not try to climb over the gate.
Some of the other safety features to consider are height (it should be taller than the baby), installation flexibility (depending on the kind of stairway or stairway frames you have), latches (so that there is a 'click' sound every time you open or close it telling you whether you have shut it well or not), and light (some of the baby gates for stairs glow in the dark). The material used to make these baby gates are wood and hard plastic. The prices differ based on brands, material, designes and size. Choose only certified baby gates for the stairs. Your baby's protection is in your hands as you already know, do not lull yourself into thinking that once these gates are installed, you can't heave a sigh of relief. You can never tell with the innovative ways of a baby. Be on guard always.