Does an older MacBook have different security needs?

There’s no panacea here.

I use the built-in security.

Twelve years go is an immense time in IT. Well before Apple XProtect, XProtect Remediator, gatekeeper and notariztion, the sealed read-only system volume, endemic app sandboxing, two-factor, and numerous other security and integrity updates, and long before the sorts of threats that are happening now.

In recent times, sources of problems include compromised cracked apps and phishing and spear-phishing and spoofed telephone numbers and such. Too much of what gets discussed around here are the “free” apps and the adware and related apps, and notification and calendar spam and ilk, as well as issues caused by add-on security apps. Some of the better-known add-on anti-malware for macOS turned out to be filled with surprises, too.

And then realize that the add-on anti-malware is itself an increasing target for exploits and vulnerabilities, as some of the add-on security apps have been atrociously poorly (insecurely) implemented.

More macOS-related security reading material:

… Personal Safety User Guide - Apple Support

… Apple Platform Security - Apple Support

… from that: Protecting against malware in macOS - Apple Support

… https://tidbits.com/2022/09/02/macoss-new-xprotect-now-regularly-scans-for-malware/

… https://www.cisa.gov/news-events/cybersecurity-advisories/aa23-215a

(biggest targets: down-rev apps and software)

Sophos security problems from around the same time (2012) as you were discussing it:

… https://www.pcworld.com/article/455572/researcher-finds-critical-vulnerabilities-in-sophos-antivirus-product.html

… https://lock.cmpxchg8b.com/Sophail.pdf

... https://lock.cmpxchg8b.com/sophailv2.pdf

Sophos has undoubtedly improved their product since then, of course.

But here's my question: about 12 years ago I hired a Mac-specialized computer consultant who recommended and installed the free versions of Sophos and Malwarebites on my then 2012 MacBook Pro. She said these were the only things needed for Mac and to run a scan once a month/occasionally.

That would be sufficient for me to fire that Mac-specialized computer consultant.

Yes twelve years is an eternity in technological terms, but I wrote that User Tip about fifteen years ago, after practicing it for much longer than that. It has needed only minor updates since then.

The nature of threats today is to exploit human frailty and frighten people into taking actions that are inappropriate or even harmful. This phenomenon is not limited to computers; you can see it all around you. It's nothing new. People succumb to scams all the time. As a psychologist you probably encounter enough of it already.