Question: Where should one perform the Sunnah Salaah: at home or in the Masjid?
Answer: It is more virtuous to perform the Sunnah Salaah at home. However, if there is a possibility that while intending to performing it at home, one may get caught up with other activities, then it is best to perform it in the Madjid.
صلاة المرء في بيته افضل من صلاته في مسجدي هذا الا المكتوبة – سنن الترمذي ج١ص ١٠٢ سعيد
And Allah Knows Best