Silver and gold have been precious to people since at least ancient times. Their wonderful shine which is useful for jewelry and coins combined with their rarity has made the value of these precious metals hold throughout the ages. Today, combined with platinum and palladium, they are used for all sorts of technology never dream possible long ago.
The reason to buy and keep precious metals is that they will continue to be precious unless a lot of it is somehow discovered using future technologies or the value system changes to such a degree physical objects are no longer valuable (that's what Bitcoin is for).
I don't see silver and gold as much as an investment. It is more of a way to save and store value. Although you can invest in mines or coins and hope those will rise, mostly precious metals just keep up with inflation. In any case, that is my outlook.
With 4 different precious metals on my outlook, I can take a look at the long term and short term graphs and usually make a choice on which metal to buy.
I wish I owned these, sadly, they aren't mine. I found it on Wikipedia
Actually, when I want to invest in precious metals I just buy paper holdings. Keep in mind this is risky as you don't actually own the metals, you only own a promise which can easily be broken. I like to buy certificates that say I own precious metals when taking advantage of short term trends. I don't think we have to worry about these certificates being useless unless there is some sort of major problem. Just make sure they are credible and insured for their value.
Another option besides actually holding physical gold or other precious metals is to pay some vault to store them for you. There are several companies around the world that will hold physical gold and metals for you and it is not a scam. They actually just keep you away from them. I know there is a vault somewhere in Singapore that does this. They say somewhere because the safest vaults are hidden ones.
For those who like to keep it on your person, if you do this, you need somewhere safe to keep it. The best place is in a safe. Sure these can be cracked or blown up, however, unless someone knows what is in there, they need to be careful opening it. Also, it's better than keeping it under your bed or in some hole. Just avoid telling people you collect and where your safe is. I recommend keeping it somewhere besides your primary residence if this is an option.
However, don't keep it all your precious metals in a single safe, get a safety deposit box at the bank and maybe another smaller safe for your primary residence or divided them into two in your house. Actually, asides from silver, you need an awful lot of value in precious metals to fill up even a phonebook sized safe.
When it comes to collecting platinum and palladium, I only stick with bars and minted coins. For silver, it is bars, collector's coins, coins that were in circulation, jewelry and basically anything pure or almost pure. Silver is heavy, especially considering its relatively low value. For gold, I collect small bars and collector's coins. I've also recently got into gold dust. This stuff is interesting, but you need a reputable buyer who checks it and then lets you check it. Fortunately few things are heavier than gold other than very rare and often dangerous elements. When I get enough dust I want to make my own custom coins and bars.
So where do I buy my gold? From the bank, the mint, the jewelry shops, etc. You can even buy stuff online if you are careful. Start with the safer places and work your way up. I don't have very much gold, but I sure like looking at the gold I do have, so I keep some of it where I can easily look at it and appreciate it. I like its shiny reflection.