replace suspension all at once ?

[tmontague]

imo, if you do the work yourself and have properly inspected the buchings and they do not have telltale signs of wear then I'd only fix what is broken/almost broken.

If you're paying to have the work done then I'd do it all at once since it will save a lot on labor.

Keep in mind that many aftermarket parts do not last nearly as long as oem so I wouldn't recommend just swapping out parts (unless you bought oem) because you have them unless you see that they are worn or are showing signs of wear.

Control arms bushings (the puck bushings at least) you can usually see wear when you jack the car up and there is no load on the suspension. You'll see smaller cracks forming - more than what is normal for rubber bushings. This is what I have on my Yaris at 175k km.

Just my 2 cents but some things to consider none the less

As a side, what's the story behind your username....scares me a little bit...