Knits ladder easily and it's scary when you see it happening on your almost-finished tee shirt! The type of needle you use will prevent this from happening.
Sharp needles tear holes through fibres, which is great for wovens but not ok for preventing ladders in knitted fabrics.You’ll need fresh ballpoint needles, they slide through the fibres. Unless of course they are blunt, banged up or too thick for your fabric. They do come in varied weights and twin needle options. We recommend testing the needle on your fabric first and changing them often. You should always change your needle after a collision with the needle plate.
Twin needles are a special needle intended to make pin-tucks for decorative sewing, but they are also are brilliant with knits. Any sewing done with these is automatically a bit stretchy. You can try your decorative stitch setting whilst using these on neck bands. They come in ballpoint and a series of widths.
Check out this post on hemming knits for a set of examples done with twin needles.