83% of spam I received last month failed at least one of these checks, while less than 2% of ham did. They're certainly useful.
But in last 5 years levels of spam never even remotely approached levels what I remember from 2000s, when my job was actually fighting it (at an ISP).
All this tech (SPF, DKIM, DMARC) came and went ... somewhere, and there was exactly zero impact in spam rates on the handful of domains I now maintain, when I did take some time to implement them.
Nowadays I have a couple of my own domains, with nothing antispam-configured, and an gmail account, and you know what -- spam amounts almost exactly match.
Hence the conclusion - it's not worth it to invest time into it.