Besides factors like SS, pensions and mortgage free housing - optimized expenses can be worth more than $880K over a 40 year retirement, without a change in overall lifestyle.
A possible sample (YMMV) -
1. Lawn vs native garden - $500 a year lower water bill - $20K over 40 years.
2. Price shop insurance, high deductible only - $1K a year lower insurance - $40K over 40 years.
3. Monthly energy bill - $350 vs $50, $3.6K yearly, $144K over 40 years
4. Renegotiate cable bill - $100 vs $50, $600 yearly, $24K over 40 years
5. Low cost cell phone carrier - $100 vs $50 yearly, $600 yearly, $24K over 40 years.
There is a $246K possible difference in total retirement funding needed with just those 5 expenses optimized vs not. Add in more and it would not be that hard to even surpass the impact of $880K in savings for some households. Financial assets are just one of many factors impacting overall financial security.