When should I start saving?
Generally as soon as you can afford to.
Although saving for retirement might not be your first priority financially, the sooner you start the better. That way your hard earned savings will have longer to grow.
By starting to save in your 20s you could accumulate a substantial retirement fund by the time you retire. If you leave it until you are in your 30s or 40s you would have to save a much larger proportion of your disposable income to provide the same level of income in retirement.