Depends greatly on what you want to power.
We have a big microwave, three air conditioners, two electric heaters and lots of electronics - and have been happy with a single 2Kw Champion which can't manage much more than 1300 watts continuous. Most of the time when not on shore power we do fine on batteries and solar. When solar is not enough, the 2Kw charges batteries just fine.
It chokes trying to run even one of the air conditioners, so when it's hot we have to have shore power.
It won't run the microwave. The electric heaters will spin up, but don't put out much heat. The small gen will run lights, big TV, ham radio with careful management, but makes too much noise.
So it runs only as a stopgap when solar can't keep up, and we do without the AC and microwave.