The draw from my 1800w inverter would use noticeable power when inadvertently left at idle and seemed like a waste to charge a phone. Added 300w inverter and cut idle current by 80% for most uses. Large inverter powers the microwave circuit and one added outlet in the kitchen. Small inverter powers the remaining outlets on two convenience circuits. Works for me.
When the large inverter gave out on our big trip last summer we lost some usability but the small stuff was good to go.
On edit:
I carry no generator so no inverter means no 120v power unless I plug in.