The standard advice in saving for retirement is rather straightforward: save as much as you can, starting as early as you can, to maximize the amount of your savings and how long it has to grow. The more you can get into the retirement account, and the longer that you can let it compound, the more affordable it will be to retire.
However, the reality is that trying to increase savings actually has a dual positive effect on reaching retirement: not only does it mean there’s more in the account to grow, but saving more reduces your retirement savings need. The reason, simply put, is that for any given level of income, the more you save, the less you’re spending to live on – and if you don’t spend as much to maintain your lifestyle, you don’t need as much saved up to replace it!
In fact, the impact of increased savings (and the associated reduction in spending) can actually go a long way to help bridge the gap for retirement, especially for late-stage savers. On the other hand, for those who are still younger, strategies that help to maintain (but not substantially increase lifestyle), and let future raises be directed towards savings instead, can dramatically accelerate the path towards early retirement as well by controlling the retirement savings need. In the extreme, highly frugal living allows for extreme early retirement, precisely because it facilitates both substantial savings, and doesn't necessitate much to achieve financial independence given that very frugality.
The bottom line, though, is simply to recognize that the reason big savers who live modestly are more able to retire is not just because of the savings itself, but the fact that a moderate spending lifestyle can dramatically reduce retirement savings needs in the first place!