Ilm is not gained, it is given. For this privilege, one cannot simply rely on the minimum; rather they must go beyond the fard and embrace the sunnah, mustahab and the requisite etiquettes of which one is cleanliness. Verily Allah loves the repentant and the clean (Baqarah: 222). The prophet (peace be upon him) would encourage one to be in wudu even if it were just before going to sleep. Be clean, have wudu, when studying the din and seeking the love of Allah.
Read Mufti Umar Faruq Lawharwi’s article, ‘Have wudu whilst in lessons of hadith‘. Islamic Studies Bulletin (DIBAJ), Issue 2. Available at http://uloom.com/dibaj/article/130824501