I am not an accountant. I have a question: Can I use credit notes instead of purchase invoices? Is it okay per accounting principles or just a way around?
This is because I have customers who are my suppliers too and I am trying to save time by adding just a credit note (instead of a purchase invoice) & avoid hassle of doing sales and purchase invoices offset through Journal Entries every now and then.
In general, no, you cannot do this. Both credit notes and purchase invoices do more than adjust financial balances. They also adjust inventory quantities and take care of posting entries to proper accounts.
There are some limited cases where you might be able to offset sales and purchase invoices with a credit note, but the risks of getting things wrong are high—especially for a non-accountant.