Al-Harith bin Suwayd narrates: Sayyiduna Abdullah bin Mas'ud (may Allah be pleased with him) used to say: "Keep the prayer light, for behind you are the elderly, the weak and those with needs." And we used to pray with our imam in our (everyday) clothes, and he would recite a surah of about a hundred verses; then we would go to Sayyiduna Abdullah (may Allah be pleased with him) and find him still in prayer.
Hadith Referenceالمعجم الكبير للطبراني / باب العين / 9250