I guess that depend on the situation.
I'm a fan of a lot of long standing IP so I guess it's normal for things to change as time pass. Some things get retcon, some design changes. Not a big deal.
I will take Fallout as an exemple. We have 30 years of games. From the first Fallout in 97 to Fallout 76 in 2018. And it's still the same world that get expanded with each new games.
And of courses the artstyle changed over the years, the gameplay and the writting did too because we don't make games now like we use to in the late 90. And I think that's ok.
And when they decided to adapt Fallout as a TV show, they could have decided to do something completely different, or to adapt one of the games but no.
They decided to make an original story set in the Fallout universe, canon to the games. So if you don't know the games you can watch it because it's an original story, but if you are a longtime fan like me, it expand the lore and the story and it's super cool !
I personnally would not have watched the TV show if it was just an adaptation or if it was not canon. Not interested.
On the other hand, some IP are so messy that it's a good thing to reboot them.
Take the Halloween films for exemple. The first one is a masterpiece but the sequels became more a more bad and silly (in my opinion) and the story became a complete mess. So I think it was a good idea to make the legacy sequel and start again from the ending of the first one.
And for Evil Dead, I think they did the best thing with the news movies. I don't want an Ash movie without Sam Raimi and Bruce Campbell, and I don't want them to erase the old movies so I think it was a good idea to focus on new characters and to start building something new in the same universe.
And I never cared if the Necronomicon doens't look the same from one film to another, or if the 3 books in AoD where not supposed to be 3 differents Necronomicons at the time, or if the end of ED2 and the stard of AoD are not the same.