He is allowed to fast on all days outside of Ramadan except for the six prohibited days – the two Eid days (Eid al-Fitr and Eid al-Adha), the three days of Tashreeq, and the Day of Doubt – due to Allah's saying: (So whoever among you is ill or on a journey – then an equal number of days [are to be made up]) Al-Baqarah: 184. This is a command for making up the fasts without a specific time, so it is not permissible to restrict it to certain times without evidence. Refer to: Bada'i' al-Sana'i' 2: 104, and Al-Hadiyyah al-'Ala'iyyah p. 173. It is obligatory to delay it according to the correct opinion: meaning it is obligatory at any time without specification, and the choice of specification is up to the person obliged. Whenever he starts to make up the fast, that time becomes obligatory for him, and if he does not start, the obligation becomes restricted to the end of his life during a time when he is able to perform it before his death. It is not timed between two Ramadans; because the command for making up is unrestricted regarding the specification of some times over others, so it remains general. Accordingly: it is not disliked for someone who has to make up Ramadan to perform voluntary fasts, and if he delays making up Ramadan until another Ramadan enters, he is not required to pay a fidyah; because it is not obligatory to compensate for fasting except in cases of inability to achieve it due to an inability that does not usually allow for recovery: as in the case of an elderly person. However, if there is no inability, then no fidyah is required; because he is able to make up the fast, so there is no reason to impose a fidyah on him. Refer to: Bada'i' al-Sana'i' 2: 104.