You usually either fix thing as they break, or take a look at the average lifespan of suspension parts and replace before they break and leave you stranded somewhere.
If none of these have been replaced yet, than at 150k km I assume you're suspension will be past it's best as may need replacing (springs, dampers, bushes), battery, cooling system refresh (water pump, belts, hoses, radiator checks), etc.
How far you go is entirely up to you, and how much value you put on maintaining a relatively low-value car.