Don't do it. Installers will usually report requiring elevation anyway. If they don't, Windows will probably ask whether the installation succeeded and give you an option to redo the process with elevation.
For incidental use, take half a second to right-click and run as admin, or type the executable's name in the start menu's search, then hit
Ctrl-Shift-Enter. Elevate an already running program by clicking its icon in the taskbar holding
Ctrl-Shift. Change the compatibility properties of a shortcut if a frequently run program always requires administrative rights. Suppress warning messages by turning off UAC if you're doing administrative stuff for a prolonged period, or log in using the Administrator account.
Don't do this by default. It might not answer your question, but it's good advice. As others have rightfully mentioned in caps and bold face, it is a major security issue, and I very much suspect anyone who is even close to capable of handling it, would know how to get elevation by default.
You will suffer all kinds of problems, even if you would never cause one yourself. Automated attacks are common and restricting an application's rights is a very effective way of keeping attackers out. Most computer owners I know who threw this security layer out the door had several botnets competing for CPU time.