Go through these in order and stop at the first one that applies. If you are reading this for someone else, answer for them.
Get urgent or emergency help if shaking starts suddenly with facial drooping, one-sided weakness or numbness, trouble speaking, severe loss of balance, confusion, or a sudden severe headache.
These may indicate a stroke or another acute neurological problem, not typical essential tremor.
Sudden severe shaking with fever, agitation, heavy sweating, a very fast heartbeat, or possible poisoning also requires urgent assessment.
Make a routine appointment for a persistent tremor, even if relatives have similar symptoms.
Other conditions and medicines can cause shaking, and family history alone does not confirm the diagnosis.
The article also says
Seek a review if:
A known tremor is getting noticeably worse
New stiffness, slowed movement, weakness, numbness, or balance problems appear
Tremor begins after starting or changing a medicine
Symptoms interfere with eating, drinking, work, driving, or self-care
Treatment causes dizziness, faintness, breathing problems, or troublesome weakness
Every sign above is quoted from the sofidex article on Familial essential tremor. If you are not sure, err upward — it is always reasonable to be checked.