If your door came with the house and the house went up around 1974, here's what usually shows up first: a grinding or scraping sound as the door travels, which is almost always a roller that's worn past its bearing. A door that hesitates or jerks partway through its cycle points to a track that's shifted slightly out of alignment over the years, common on a foundation this age settling unevenly.
If the door feels heavier than it used to when you lift it manually, that's the torsion spring losing tension, not the door getting heavier. And if you hear a loud bang from the garage on a cold morning, that's very likely the spring itself finally letting go under the combined weight of age and cold steel.
None of these are emergencies you have to solve alone, but none of them get better by waiting either.