This is how it works. The prices are different in different countries. Most countries have renewals due every year. Many countries have increasing costs each

This is how it works. The prices are different in different countries. Most countries have renewals due every year. Many countries have increasing costs each year, and costs vary between tens of dollars and thousands of dollars. Costs are also categorized between "Micro", "Small", and "Large" entities. Different countries use different numbers of these categories. The US uses all three. Some countries have fees per claim in the patents. In the US, the renewals are only due 3 times, every 3.5 years after the grant of the patent. The renewals cost $1,600 for the first renewal, $3,600 for the second, and $7,400 for the third. Those are for large entities. Small entities are half the cost, and micro are 1/4th the cost. Renewal fees, world wide, are a non-negligible part of a legal department's fees, and abandonments do happen before they otherwise would because of the cost to keep non-useful patents around.