Do I need to pay for both iCloud and Google One storage?

That is up to you entirely and how you sue the storage provided by each. It's impossible for us toteil you if you need them or not. Only you know what you may be using each for.

They are entirely separate companies and services. You cannot backup iOS devices to Google's storage, you specifically need iCloud for that, and you cannot store Google content such as Photos in the Google Photos app, of email in your Gmail account on iCloud, you need Google storage for that.

So verify how you are using each storage space and see if you need both for everything you are storing.

Remember they are separate services and you cannot use one with things that require the other.

I will add the caveat that if you are synchronizing photos to iCloud Photos and to Google Photos, be very careful about what you delete.

If you have set things up so that deletes will be synchronized everywhere, you don't want to, say, delete a lot of photos to "free up Google storage", thinking that you would still have the photos in iCloud.

Servant of Cats wrote:f you have set things up so that deletes will be synchronized everywhere, you don't want to, say, delete a lot of photos to "free up Google storage", thinking that you would still have the photos in iCloud.

Wow-- that sounds dangerous! I'd guess that, if you're thinking of backup, you should use one of the services and also use an external drive. If you have multiple Apple Devices, like an iPhone, an iPad, and a Mac, then iCloud is certainly the best choice. If all you have is a Mac, then it may not matter. iIf all you have is an iPhone, then you have to decide if backing up all your apps, mail, messages, and iOS stuff is important to you.

I don't use Google Photos--does Google let you save storage space on a phone with something like "Optimize Storage?" From scanning their site, I think they don't.

Re: “Wow-- that sounds dangerous!”

Just passing along a caution I once read about somewhere else. I believe that this may have been the article that pointed it out:

https://lifehacker.com/why-you-should-un-sync-google-and-apple-photos-1848762896