Hi,
Last year(2018) I ended up filling the generator in November--and then not using it for about 12 months. I started with premium fuel which doesn't have ethanol and used the recommended amount of seafoam.
On November 21, 2019 I was using the generator--and after about 3 hours in eco mode it shut down. I looked at the fuel and it had a milky look. I bought some gas line deicer and added some. I topped up the fuel with premium--and the generator returned to life.
I'd say the lifespan for seafoam is a little less than a year.
