@susanitaq8 FDs are only good for capital preservation, or rather minimum depletion of capital.
Only thing that they are good for, are to keep your emergency money there. This is the money that you might need in a very unplanned manner, and it may happen during a market crash or during a recession, when you lose your job. Having to sell your stocks at 30-40% losses to run your house, may wipe off any returns that you have made for a while.
Another value is to keep your money safe after retirement. When an effective 1-2% depletion (inflation minus post-tax returns) doesn't matter as much as keeping the money safe, and its availability for emergencies matters. But even then, it's better to divide the money across equity, debt & FDs.
They are also good when you have just started out earning, or are in lower earning bracket, and till the point when investments & emergency savings aren't very different. This is one aspect that a lot of well-intended folks forget, because they don't have the same problems.
But once you are beyond the stage, and once your emergency fund has reached 6 months of expenses, you should pretty much forget about FDs.
If you are in highest tax bracket, FD's post tax returns are just pathetic. One may even say that charging 30% tax on any investment's returns, is almost a criminal act by any government. But it is what it is.
I have been in both states. There was a time when just saving money was a struggle. I used RDs to save some money every day, to create a cushion for me, in case anything desperate comes up. And for such purposes, RDs & FDs are better than MF/stock SIPs. But even then I will suggest that if can afford to put some money in equity, do it. Especially if your parents can cushion you for few years. In my case, by god's grace, there were no emergencies.
Once I reached 1-2 lacs in savings, I stopped putting any money in FDs "for investment purposes". These days, only thing I use FDs, is to park some money till there's a buying opportunity in the market. I have my SIPs running, for investments. And I push in some lump-sum money, whenever markets crash.
I increase the existing emergency funds in my FDs, only when there's a sensible reason that indicates increase in monthly expenses. (expenses, not income)