Daylite stores its data in a SQL database and the raw files are located in
Hard Drive -> Library -> OpenBase -> Databases
(Note that these folders are NOT in your home folder).

If you upgraded from v1.7.3 or below, your databases will still be located in
Hard Drive -> Library -> OpenBase -> Databases

However, if you made a fresh install of v1.7.4 and any versions upwards, then your databases will be located in
Hard Drive -> Users -> Shared -> Databases.obstorage

If you do not find your databases in any of those locations, check the contents of the following file to see where the databases could be located
Hard Drive -> Library -> OpenBase -> Config -> DatabasePath

Databases.obstorage is package.
To see the contents (where the actual databases are), do a 'Show Package Contents' in the Finder (using the contextual menu).

Daylite does not interact with these files directly, instead, Daylite talks to a process called 'OpenBase' to get all its data. OpenBase is what controls the raw files.

Please do not move databases to different folders or do not restore databases without following the proper procedures (as outlined in the Knowledge Base or in some of our movies).

Typically you will never need to worry about the databases, because OpenBase is a highly resilient system.

Please perform the regular 'quick backups' from the toolbar.
You should also consider setting up a nightly backup process.