By the time fixed costs eat up the majority of our income, an extra $500/month represents a large fraction of our discretionary income.
While my retirement calculations do only vary a few hundred a month in extra spending by taking SS early or late, due to all the other factors, you are increasing the size of a substantial COLA'd annuity by 75%. For both DW and I SS will run about $1776/month at 62 or $3109/month at 70, each. It is a big impact.
This is why you must perform the financial calculations accurately, instead of the quick-and-dirty SWAG like saying "I'll need that $500 more." That's why I poured so much investigation and work into the spreadsheet that was referred to upthread.
In order to get $2000/mo at 66, you have to forego $1500/mo for 4 years, from 62 to 66. If you don't collect it, then clearly you also cannot spend it. So what if you do something similar, where you likewise do not spend it.
Suppose you do the simple method of saving the early payment until the later age and then make withdrawals from the savings account to supplement the SS benefit, so that the total of "withdrawal + SS check" is equal to what the "later" benefit would be. This is the "Quick BE table" sheet on that spreadsheet.
If the savings account earns zero interest, it would grow to $72,000 (48 * $1500) by the time you hit 66. If you then withdraw $500/mo, it will take 144 months (12 years, or age 78) until the account is depleted. Note that your total income will be the same $2000 that SS would have paid -- $1500 SS plus $500 withdrawal.
If you earn 3% it will last for 193 months (16 years, or age 82).
If you earn 7% it will last for 582 months (49 years, or age 115).
To earn 0% is easy. How difficult would you consider it to be to get 3%? 7%?
FWIW, BND is currently yielding 3.1%. My own portfolio of preferred stocks and various income ETF's & CEF's is currently yielding a tad above 7%.
PSA, a well-regarded REIT company, yields 3% and has a number of preferreds yielding around 6%.
O, another well-regarded REIT, yields 4.5%, and has preferreds around 6.5%