So I've been doing some drone work for a client who is usually very reliable and quick when it comes to paying me. The longest he's ever taken to pay me for a job was 10 days, but the last one I did, it has been over two weeks and I haven't heard anything. There's no rush on my end but would it be OK to shoot him an email to see what the payment status is? I don't want him to think I'm being impatient. Problem is that we never really worked out any kind of formal conditions in terms of when payment should be made after work is delivered.