we have got two of these at the moment both from ALDI, we left one unsed for almost 2 years and it still started, it did smoke a bit at first though! And i have never measured the oil yet I just stick a good dollop in and away they go! I have even used engine oil when out of two stroke oil (I wonder if veg oil would work :lol: )
They do recon if you turn the fuel tap off and run the carb dry it is better for storing it, but i have never bothered and not had any problems.
The only thing i have ever had play up on one of these, and it was a few years ago when they were pretty new to the market, it was a Clarke tools one 650 watt and cost a fair few quid back then about £185 I think, anyway! it used to stop putting power out when it was hot, it turned out to be the earth conections on it, i squeezed the terminals tight pushed them back together and off it went for another few months! I sold it in the end!