"if you co-lo provider sucks, you can move and keep your IP space. (This is vital for email, but I recommend it for everyone)."
Why is this "vital for email"?
I agree that obviously if you can you want your own space.
But if you are planning your move you can handle the new ip space by dns ttl. Which is what we have done since the 90's with moves where we didn't have our own IP block. And yes it is a huge pain to be avoided so I'm not disagreeing just wondering about the "vital for email".
These days making sure email gets through is about jumping through a huge amount of hoops and having a long term "trusted" track record at the domain level, ip level, etc.
Spammers have gotten good, and because of that anti-spam efforts have had to increase their restrictiveness over time. Because of this reliably getting email out of your network and into another inbox is anything but trivial these days.
Why is this "vital for email"?
I agree that obviously if you can you want your own space.
But if you are planning your move you can handle the new ip space by dns ttl. Which is what we have done since the 90's with moves where we didn't have our own IP block. And yes it is a huge pain to be avoided so I'm not disagreeing just wondering about the "vital for email".