Since 1981, CHANGES of note for me:

Used LF lenses available at discount prices
NEW HIGH QUALITY LF cameras made in China can be shipped to your door
Take care of your film holders; new ones will likely need to be custom made; though used ones are still easy to get.
Used LF enlargers are available at discount prices
High quality multigrade paper is available from multiple manufacturers (but not Kodak).
Ten years ago Densitometers and Sensitometers were available for a fraction of their new cost but maybe not so in the last 3 to 5 years.
Good enlarger alignment tools available (Laser or mirrors).
MTF is used more commonly than lines per millimeter for describing lens performance.
Hansma described an optimum shooting aperture that takes into account diffraction and de-focus.
Selenium probably does not aid B&W print longevity
Although concentrated hypo poured into a print washer goes straight to the bottom, the usual dilute hypo, that would be present during print washing, is probably distributed evenly throughout the moving water
Microfiber lens-cleaning cloth

Since 1981, the SAME:

Beginners you might meet or teach still like underexposing and over developing negatives
Fiber Based Paper archival washing sequence is nearly the same.
Still, no one knows if RC paper is archival
Spot meters are still pretty expensive
New Jobo processors are still expensive
Six element enlarging lenses are still the best
Darkrooms still use a conventional amber or red safelight!
Multigrade paper still uses GREEN (low contrast) and BLUE (high contrast) sensitive layers, though the Ilford Contrast Filter set has changed since 1981.
Commercial film speed ratings are still based on the work of Loyd Jones
"Silver Bullet" chasing is more prevalent. On the Internet everyone is a self proclaimed expert touting the latest-greatest concoction of lens, film and chemistry. From tea leaves and vitamin-c to motion picture film cut to sheet film sizes. It seems like without a mentor it might be impossible to make logical sense out of it.