Give your ideas a marinating period before you do any work on them, say a week. But during this time vet the idea with potential customers.

After the marinating period and based on the responses you received you’ll have a better idea if it’s an idea worth tackling or not.

Monthly because it’s rare I feel confident enough to pay a year’s worth of a service at first, unless it was dirt cheap, and it gives me as the customer extra insurance that I can stop my subscription without extra headaches compared to annual (can I get a pro-rated refund? Do I have to follow up with you in a year to really make sure I don’t get charged again?)

I use Receipt Bank for collecting receipts + entering the data (RB gets new receipt data right about 80% of the time and then I can use rules to make future ones correct).

Everything then goes into Xero for reconciliation with my bank/credit accounts and is what my accountant checks at the end of the year to prep taxes. Been using this system for about 3 years and has been good to me so far.