I have been playing "NH" gigs (retirement communities, rehabs, nursing homes, senior centers, etc.) for ~20+ years or so; plus I play lots of functions that have a wider age-range of people. So have gradually developed a decent sense of "what the like/want to hear".

I have noticed (As others have mentioned) that now more than ever, the people in the "NH" types of places love the early rock'n'roll; music from 1950s-1960s and even some 1970s. 20 years ago, that was not what they seemed to want; back then, it was music from the first half of the 20th century (mostly 1920s-1940s music).

Since "time marches on", the people who today are in their (age) 70s, 80s and 90s, are 20 years different than people in the ages 70s, 80s and 90s from a couple of decades ago ... so I started moving from purely 1920-1940s music, to add some 1950s tunes, and in the last few years, even music from 1960s and 1970s. I think they like the "energy" of the early-rock-n-roll and R&B type tunes!

I still do a good number of 1930s-1940s song, and an occasional classical piece, as there are people who like those too.

As far as "MUST DO" songs/styles, ones that either go over very well, or are requested time after time, there are many - here are a few that come to mind: "Tennessee Waltz", Sentimental Journey, In The Mood, Moonlight Serenade, most any Sinatra tunes, some musical-theatre songs from shows that were popular a few decades ago, Elvis tunes, Beatles tunes - and in recent years, I find they are asking for Eagles tunes!

So, there is a LOT to choose from that will please these audiences!

-Jim