Machu Picchu

It all depends on what you are doing and if you use trek poles frequently. I don't and when I went at 53, didn't need them for just visiting the site for the day. If you plan on hiking up other trails or doing an Inca Trail trek, then they could be useful.
If you have stability issues, then they may be helpful as the main site has areas of rubble and rolling terrain.

I was not unsteady on my feet when I went to Machu Picchu but I bought a pole/cane at a local market in Peru before going to the site. The rise of some of the stairs at the Machu Picchu are quite deep so it’s a big step down. Plus some of the staircases are pretty steep and there are no handrails. I found having some kind of poles to be useful there.

We didn’t need hiking poles when we were there. If you make the climb up Waynapicchu there are ropes to hang onto on the steep parts.

We didn't hike up to MP, so I can't help regarding the hiking trails, but on the site of Machu Picchu, we found the steps to be smaller than those in modern buildings and of course since they were in stone somewhat uneven.

Canes or poles may be helpful, but you would be placing the poles on stone. I was 71 when we did MP and managed just fine, although after a full day up and down the hills of MP we were very tired.