If you want something done right...

[ducks4you]

If you think you need a heavier needle use it. You can always test on a scrap of fabric, but thinner needles can snap if stressed. USUALLY, they break and are attached to your thread. Sometimes they go flying.
I rehomed my older metal trash can with a lid (where you step to open) to my sewing room so that broken needles and bent pins wouldn't get stepped on by falling out of a plastic trash can. Just some fyi.
NOTE: If you err and use too heavy a needle it can just snag the fabric, which is why testing is always a good idea.
DD's think it is magic when I ease in a sleeve!

 

[AMKuska]

So far I've mainly been working with super light weight cotton. The leggings were my first stretchy fabric, but also thin. I haven't broken a needle yet