My scheme…
1. All email accounts are IMAP. They can be accessed anywhere on any system.
2. Contacts and Notes are Google. Could also be Yahoo, or any other other service. Cross platform.
3. Photos are backed up by Dropbox. Instantly available to all Macs/PCs running Dropbox. Since these are then 'local' to each computer they get backed up daily in that computer's normal backup and weekly to Dropbox.
4. Messages. Any important photos in Messages are backed up to Dropbox by saving to the Camera Roll. Aside from that, nothing important is ever discussed via iMessage or SMS. It's all face to face, in person. This is the least bit of data I'm concerned about.
5. Voicemail is the same way as Messages. I have never had any VM that was so important I needed to actually save it off my device though.
6. Apps. Here, I don't care. For important apps, I have all my login credentials. That data is saved on the provider's systems. Just redownload the apps and log back in. Everything else isn't important to me.
I do have a 2TB iCloud sub, but it's for convenience not backup/storage.