Should I store start time, end time, and days as separate fields or use a CRON expression in my database?

I am developing a scheduling feature in my application where users can set specific time ranges and days for recurring tasks. For example, a user might configure a task to run every Thursday and Friday from 15:00 to 16:00.

I need to store these schedules in my database and am debating between two approaches:

1. Storing start time, end time, and a list of days as separate fields.
2. Using a CRON expression to represent the schedule.

Here's a simplified version of the current approach using separate fields:

• start_time: "15:00"
• end_time: "16:00"
• days: ["Thursday", "Friday"]

Alternatively, I could convert these schedules to a CRON expression in UTC:

• CRON: "0 15 * * 4,5"

Considerations :

• Time Zones: Users configure times in their local time zone, but the application needs to store and process these times in UTC - Maybe it is better to store it as UTC, right?

• If a user change it's time zone, for example he moves from time zone A to B, I will have to update all it's schedules stored in database, because the time (15h-16h) should be the same.

• Users have a date picker. it's easier for them to use date picker instead define a cron.

Questions:

• Which approach is generally recommended for storing recurring schedules in a database?
• Are there best practices or common patterns for handling such scheduling requirements?

Thank you a lot!