A torsion spring holds enough stored tension to cause real injury if it lets go while someone's working on it, and that risk doesn't change because a house is older or newer. We don't recommend homeowners touch spring replacement or cable work themselves, full stop.
What you can reasonably check yourself: whether the door is binding on visibly bent track, whether rollers are cracked or missing, and whether the opener's safety sensors (the small eyes near the floor on each side of the track) are aligned and lighting up. Those are visual checks, not repairs.
One honest limit: if your door and opener are both original to a house built in the early 90s and showing multiple problems at once - spring, opener, and rollers all worn together - patching one piece rarely holds for long. At that point full spring and roller replacement, sometimes with an opener swap, usually costs less over two years than a series of one-off repairs.