Shiva Purana
नात्यन्तं करणीयन्तु मुमुक्षोर्मन्त्रसाधनम् ॥ कृतन्तु तदिहान्यत्र तास्यापि शुभदं भवेत् ॥ १० ॥
A devotee who desires salvation need not practise the mantra too often. If practised moderately it is auspicious here and hereafter.
english translation
nAtyantaM karaNIyantu mumukSormantrasAdhanam ॥ kRtantu tadihAnyatra tAsyApi zubhadaM bhavet ॥ 10 ॥
hk transliteration by Sanscript