Our rules state that plots should be cultivated to 90% of their potential. In practice many of us only aspire to this, at least for the first few years. The committee are generally tolerant of new growers who are still finding their feet, or reliable members whose allotments are neglected for a short while.
The most important general guide is that your plot must look like a work in progress. The committee must see that things are going on, and you are heading for 90% cultivation, however imperfectly.
We understand that life is complicated, and health and personal issues can get in the way. However, neglected plots have an impact on other members, and a plotholder who has clearly not done much to their plot in a long while may be asked to leave. There are no refunds on rent in such cases.