He said to the Messenger of Allah: "Can I wipe over my leather socks?" He said: "Yes." He said: "For one day?" He said: "For two days?" He said: "For three?" And so on, until the number reached seven. He (the Prophet) said: "For as long as you see fit."  

عَنْ أُبَىِّ بْنِ عِمَارَةَ وَكَانَ رَسُولُ اللَّهِ ﷺ قَدْ صَلَّى فِي بَيْتِهِ الْقِبْلَتَيْنِ كِلْتَيْهِمَا أَنَّهُ قَالَ لِرَسُولِ اللَّهِ ﷺ أَمْسَحُ عَلَى الْخُفَّيْنِ قَالَ نَعَمْ قَالَ يَوْمًا قَالَ وَيَوْمَيْنِ قَالَ وَثَلاَثًا حَتَّى بَلَغَ سَبْعًا قَالَ لَهُ وَمَا بَدَا لَكَ  

He came to 'Umar bin Khattab from Egypt. 'Umar said: "How long has it been since you have taken off your leather socks?" He said: "From one Friday to the next." He said: "You have acted in accordance with the Sunnah."  

أَصَبْتَ السُّنَّةَ