Beyond knowing your pet’s behaviour, which is already a good warning sign, it is necessary to objectify its feelings. Why is this necessary?
In nature, most exotic animals are prey. As a result, they instinctively mask their vulnerabilities so as not to attract the attention of predators. This often means that when you notice that your companion seems to have a problem, it has been sick for several days. An ailment that would initially be easily managed quickly becomes an emergency. So in these species, you need to react very quickly!
Moreover, even if you handle your pet every day, its small size and rapid metabolism are factors conducive to the rapid progression of a disease.
This should be contrasted with the situation of reptiles, which have a much slower metabolism than mammals and birds. A sudden weakening of your reptile’s condition is generally an acute decompensation of its organism in the face of a chronic pathology that has been present for several weeks/months.