We have had this argument more than once here, and the overall consensus is to always use braces. TheThe main reasons are about readability/maintainability.
If you need to add code to the ifif block, you don't need to remember/search for braces. When future programmers read the code, the braces are always unambiguous.
On the plus side, resharperReSharper will automatically add the braces for lazy programmers in visual studioVisual Studio, and I assume there are addons for other IDEsIDEs that will do so as well.