I'm a bit shocked that all answers so far use cloud storage and not a single one proposes offline.
I store everything in the cloud, because it is unbeatably convenient except for the very things mentioned: health, financial and legal. I'm not 100% strict either, because if a document has been sent or received electronically or can be assumed to be stored in the cloud anyways I really can't do much. I still assume that every online storage will be breached one day and keep some documents deliberately offline.
To give you some chills, check out "Who's been pwned" [1] and this is only the tip of the iceberg that has surfaced and that fulfills HIBP's inclusion criteria.
besides the security aspect (which I agree is major and often unavoidable), local storage has numerous other advantages, among which: (1) search can be dramatically and noticeably faster, (2) access cannot be removed/degraded when traveling to countries in which various online services are not permitted.
I store everything in the cloud, because it is unbeatably convenient except for the very things mentioned: health, financial and legal. I'm not 100% strict either, because if a document has been sent or received electronically or can be assumed to be stored in the cloud anyways I really can't do much. I still assume that every online storage will be breached one day and keep some documents deliberately offline.
To give you some chills, check out "Who's been pwned" [1] and this is only the tip of the iceberg that has surfaced and that fulfills HIBP's inclusion criteria.
[1] https://haveibeenpwned.com/PwnedWebsites