How likely will a stroke lead to disability?

Depends on severity: The likelihood of a disability from a stroke depends on the severity of the stroke, the type of stroke (hemorrhagic vs ischemic) and how quickly one seeks emergency treatment for the stroke. Any suspicion of stroke symptoms warrants immediate emergency care.

Very likely: Almost all symptomatic strokes cause deficits, which if permanent can result in disability. Many immediate deficits resolved without residuals. Interestingly with the advent of MRI scans many people have diagnosed with "silent strokes", those which never cause detectible symptoms.