In Jain tradition, there is no fixed rule that you must chant exactly 7 or 8 Navkar Mantras before sleeping.

A simple and common practice is:

• 1 time with full devotion, or
• 3 times as a regular nightly practice, or
• 9 times if you want a little more japa.

What matters most is:

• shuddh bhav,
• faith,
• ekagrata,
• and remembering the Navkar Mantra with reverence before sleep.

So, if you are asking “7 or 8?” — neither is compulsory. You may chant as many as you can with calm and devotion.