If my wife (born in 1956) delays filing for benefits on her work history and spousal benefits after her FRA, will her benefits be higher due to DRC's than just her PIA plus excess spousal benefit (ESB)? I was born in 1953 and don't plan to file for benefits until I'm 70.
I'll answer your question with an example. Sally's full retirement age benefit rate (PIA) is $800. Her husband, Art, is drawing his benefits and has a PIA of $2000. If Sally files for benefits at full retirement age (FRA), she will receive $800 on her own record, plus $200 (i.e. $2000/2 - $800) as a spouse on Art's record. Thus, her combined benefit rate of $1000 would equal a full 50% of Art's PIA.
However, if Sally, who was born in 1956, waits until age 70 to apply, her own retirement rate will be increased by roughly 29.33% due to delayed retirement credits (DRC). That would raise the rate payable on Sally's own record to roughly $1034 (i.e. $800 x 1.2933), which is more than 50% of Art's PIA. As a result, Sally would not be eligible for any spousal benefits from Art's record.
By the way, since you were born prior to January 2 1954, you can still potentially file for spousal benefits at FRA without also filing for benefits on your own record (https://www.ssa.gov/planners/retire/deemedfaq.html). Your wife would need to be drawing her benefits in order for you to be eligible for spousal benefits, though. You may want to strongly consider running the maximization software available on this website in order to determine the best filing strategy for you and your wife.