Painted glass can last for decades, and most breakages happen in January, not on the tree (sample note).
Take the baubles down first, before the lights. Wrap each one in a sheet of tissue, never newspaper, which can mark the paint. Stand them in an egg box or a box with card dividers.
Keep the box in a dry cupboard in the house. Lofts get damp and swing from cold to warm, which loosens the caps.