Belgium is a fairly expensive place to live, and the relatively high taxes of various forms, plus the need to have medical insurance, should be taken into account if you plan to retire there. However, Belgium does have double taxation agreements with many countries and if covered by one of these you will not be charged twice on your income when living in Belgium.

For expats from many western countries including the UK and US state pensions can generally be paid to them direct in Belgium, and they will benefit from any increases in the same way as if they were in their home countries.