Why are you backing up? To protect accidental changes to files? To protect against ransomware? To protect again a lost computer? Understanding why, will help decide what method to use. It is often best to keep a local offline backup, and also an online cloud one. And don’t backup ancient data :)

To protect against broken and lost computers, mostly. I do have an offline backup but want to get an online up and running, just in case. You never know!