Great question! The habit of savings can vary from person to person and certainly depends on what stage of life you are in. When I was in college, I used to skip a couple of lunches a week (only after a heavy breakfast of course) and sometimes walk back home and save my bus money. I needed the money to buy second-hand editions of The Economist, which were expensive in India.
But once I got a steady job I would aim to save 15% to 20% of my monthly pay into a savings account. The best way is to have a monthly direct debit set up from the checking account. Most savings accounts these days offer higher interest rates if you save money for a long term period, say three to five years. My goal used to be a accumulate a fixed some of money — say equivalent of $1,000 — and then put it into a high yielding savings account.
Once my income started going up, I started investing in the stock market. Not picking individual stocks, but investing in index funds. In the U.S. the S&P 500 Index is always a good start. The Russell 2000 index is another one that one can put money in and see savings grow at much higher rates compared to putting money in a savings account.
Irrespective of your lifestyle, saving 10% — at least — of your income every month should be mandatory.