Has Rasoulullah(SAW) observe i'tikaaf?

Yes, the holy prophet SAW observed i`tiqaaf the whole month of Ramadhaan 3 years before he passed away. He objectively sat for I`tiqaaf looking for lailatul Qadr. On the 20th Ramadhaan he announced to his companions following him in I`tiqaaf to continue the i`tiqaaf because he did found the night of qadr yet. So he finally found it in the last ten days. And hence the following years of his life he observed i`tiqaaf of only the last ten days of Ramadhaan. As such it is sunnate muakkadah alal kifayah for at least one man to sit in i`tiqaaf in a masjid in a particular area. Please read the article on the web on its principles and virtues.