Well I keep my Windows up to date without any reward so I thought maybe its best to update the BIOS too as people say its good to keep your BIOS up to date.
Updating Windows isn't a good analogy for updating the BIOS. The rewards for updating Windows are normally not obvious---you update and don't see any difference, but you are probably avoiding issues in the future by doing it.
You can typically recover easily from a Windows Update if necessary. Not so with a BIOS update that goes bad.
I don't hear most people say "its good to keep your BIOS up to date". Some people update mostly because they heard it's a good idea without investigating or because they are obsessive/compulsive to some degree.
It's like drivers. Some people insist on getting the newest drivers when the current driver is working well without issues. But drivers can be easily rolled back.
I'm not having any BIOS issue at the moment so I guess I shouldn't update but if I ever should need to it would be useful to know what version to pick? How it works? the risk if failure screwing up the pc?
If you are having problem X, you should look at the notes for the newer BIOSes and pick one with notes that say something like "fixes problem X".
It takes 5 or 10 minutes. The onscreen instructions are often not clear. You could easily make a mistake. If it goes bad, you either need to get a new motherboard or pay to have a new BIOS chip installed, which is probably more trouble than simply replacing the board.
If you don't have a power failure and in fact understand the instructions, it should go well. But it's a pointless exercise if you don't get an obvious benefit---a problem disappears, you can use some different hardware that you want to buy, whatever.
I've done it a number of times. Once or twice I needed to do it to fix problems or support new hardware. The other times I did it because I enjoy temptation and was willing to take the risk for no known benefit. Foolish, but I did it successfully. It fixed nothing as I was having no issues. I'm as obsessive/compulsive as the next guy.