The subscription billing date is currently set by the first day of the subscription (if you start it on Jan 10th, it will renew on the 10th of each month).
I suggest a way to set a different date (day of the month). Ideally it could be changed for existing subscriptions, otherwise just a setting for new ones.
Kagi uses Stripe, it looks like it's a setting.
For budgeting reasons, I prefer all my recurring bills to get charged at the start of each month (just after I get paid). To change the date for Kagi I had to cancel it, wait some time without access to Kagi, and restart a new subscription at my preferred day of the month.
With this feature I could have set it directly. The charge could be calculated proportionally for that month, just like when you change your plan.
