Previously, a conservative interpretation of the rules was widely posted online as saying:
To prevent losing a residency visa, the visa holder may be outside Ecuador for only 90 days in each of the first two years after obtaining the visa, and a maximum total of 18 months during the first five years -- including time outside EC during Years 1 and 2.
However, the Cuenca-based Gringo Visas company, which aids Expats in obtaining such visas, has a different take:
"For the first two years, a person cannot be out of the country for more than 90 days each 12-month period.
"But starting from the third year forward, a person can leave the country for as much as 18 months at one time, and not lose their visa. For example, in the third year a person can leave for 16 months, return to Ecuador for a few days, and have another 18 months available to leave the country."
source: gringovisas.com