What is "decompensated" liver failure?

I don't know if I've misunderstood this but I've found it very difficult how to classify a patient as "decompensated" liver failure and hence when to do the relevant investigations for these patients (e.g. ascitic tap (apart from ?SBP when they are tender), ammonia level, etc etc).

How do you tell when they've decompensated? I find it easy to diagnose decompensated cardiac failure - combination of oedema, breathlessness and an echo is usually diagnostic. However I feel like it's not the same for decompensated liver failure - a lot of cirrhotics are "normally" jaundiced and "normally" have ascites. Is there a better way of viewing liver failure that can help me characterise decompensation?