Reference: Fataawa Ramadhaan – Volume 2, Page 752, Fatwa No.764
al-Fataawa libni ‘Uthaymeen – Kitaab ad-Da’wah, Volume 1, Page 187
Question: We notice some of the Muslims neglecting their prayers throughout the months of the year, and when Ramadhaan arrives they hasten to [perform] the prayers and the fasting and reciting the Qur.aan, so how is their fast (what is the ruling) and what is your advice for them?
Response: Their fast is correct, since it is not associated with anything which spoils it. However, my advice to them is to fear Allaah (Subhaanahu wa Ta’aala) with regard to themselves, and to worship Allaah (Subhaanahu wa Ta’aala) according to that which has been legislated upon them at all [their respected] times with all their abilities. The person does not know when death will suddenly strike, and it is possible they are waiting for the month of Ramadhaan to arrive and do not [live to see it]. Allaah (Subhaanahu wa Ta’aala) has not [specified] for his servants any limit except the death, as He (Subhaanahu wa Ta’aala) says:
…i.e. until death approaches you, which is a certainty.