As long as you do not develop drug resistance, the same drugs can work for years or even decades.
This involves getting viral load to undetectable (less than 50 copies/mL).
This is also why it is important to take your drugs on time, to follow advice on taking with or without food, and to not miss doses.
Around 19 out of every 20 people (95%) in the UK whose viral load stays undetectable for the first year, will continue to be undetectable for each following year.