If symptoms come and go, they are likely to be benign.
Paraesthesia (a burning or prickling sensation) due to peripheral neuropathy is usually persistent (although variable) and if related to Multiple Sclerosis (MS) tends to worsen over a few days and plateau for several weeks before improving. If related to MS, it will also rarely be in the distributions shown in the diagram and described in the more detailed descriptions below.
In particular, if symptoms are lasting seconds or minutes then you can be generally adopt a ‘wait and see’ policy.

Notalgia paraesthetica - numbness / itchiness medial to scapula
Describes an area of paraesthesia, which is sometimes itchy, in the medial scapula (where you can’t itch). It is benign but annoying and there is no investigation or treatment required.
Facial numbness - usually migraine or hyperventilation
Intermittent facial numbness is common with migraine, also in hyperventilation (where there may be perioral or tongue numbness).
Intermittent genital numbness
This is nearly always benign and commonly associated with chronic pelvic pain. Think about cauda equina/neurosurgical referral if there is sphincter dysfunction and/or sciatica or leg weakness.
Carpal tunnel and ulnar sensory symptoms
Often affects whole hand These are common in the population. Advise a wrist splint to be worn at night for 12 weeks in suspected carpal tunnel syndrome. Advise avoiding leaning on elbows, prolonged elbow flexion, especially at night for ulnar nerve symptoms. Patients with sensory symptoms only should usually be managed conservatively.
Intermittent sensory disturbance in toes or burning in feet
If sensory disturbance is only in the toes, it is rarely due to a neurological disease. Watch and wait. Similarly, patients with burning sensations in their feet but normal ankle jerks and no clear sensory disturbance rarely require neurological assessment.
Meralgia paraesthetica
Meralgia-lateral cutaneous nerve of thigh This is common especially in the obese population. The patient will characteristically be able to draw an area with their finger around their anterolateral thigh which is numb or paraesthetic. The management is explanation, weight loss where appropriate and avoiding tight clothes around the inguinal region.