Actually, it it much better to set the pagefile to a set size, with the initial size and maximum size the same. This will reduce the amount of fragmentation of the pagefile because it will not be constantly resizing itself. This can enhance performance theoretically -although with an SSD this may not be a noticeable performance gain. The only downside to this is that you will lose some gigs of space (which can be at a premium on SSD's) permanently.
As far as the size of the pagefile, the old school of thought for prosumers/gamers is to set it to 1.5 - 2 x amount of RAM. Obviously, this is not as necessary nowadays with the average amount of installed RAM being >8GB, and outside of bench-marking and some specific applications most people will not be tapping out their RAM. Following the old way of thinking, with 8GB of RAM you would set the pagefile to 12 or 16GB -this is fine if you have the available space- but not necessary.
What I do, and have been for a while, is just setting the pagefile to what Windows recommends on the config window. This varies by system. On my rig, it recommends 4980MB (~5GB). So i have the initial and maximum size set to this. It is important to note that you do need to have a pagefile set, no matter the size, as some applications are coded in a way where a pagefile is expected/needed and if one is not present the app may not run or crash. Also, Windows uses the pagefile for debug purposes, and when a system crashes a mini dump file is written, Windows needs at least 250MB for this purpose.
Another trick is to put the pagefile on another partition or drive other than the C: drive. This can save you some space on your system drive, and theoretically can help in performance as Windows will not have competing I/O with the pagefile and the system file/folder which is constantly being accessed as your system is on.
Hope this helps!