I've been investing for six years, and I have not been investing in bonds, because of the cons. I've been bullish on the stock market. Now let me go into the pros and cons of bonds.
As for the pros, there are a few of them. First, bonds tend to be more stable. In other words, they do not fluctuate as much as stocks. Some stocks are incredibly volatile, such as oil. Oil this year moved with ferocity. Second, because bonds are relatively stable, they can prove a level of predictable income. This is better as a person gets older, where less risk is better. Finally, some bonds, like U.S. Treasuries, provide liquidity. This means you can sell out when you want.
As for cons, bonds do not make as much money from a historical point of view. Stocks have done better, in other words in the long run. Second, bond prices go down when interest rates go up. It seems like the Federal bank will increase rates. So, bonds will go down.
In the end, it is best to have a diverse portfolio.