I would love the ability to enable or disable invoice reminders per-client instead of per-invoice or globally.

Some clients are business/enterprise who send checks on the due date and pay reliably. When reminders are enabled, they end up having to waste time chasing down proof of payment even though I know it'll show up in a few days.

Some clients are individuals or SMBs that need payment reminders, which is why I have them enabled globally by default. I'd like to opt-out for the enterprise customers so we stop wasting our time and theirs.