The new job provides greater income or perks. This might happen if you have achieved the greatest income bracket in your current professional path. You may need to shift occupations in order to make more money or get better perks.
You wish to attempt a more difficult job. If you don't feel like you're learning or advancing professionally in your present work, you can consider switching to a more demanding or exciting one.
Your present occupation does not promote a healthy lifestyle. A new job may provide you with a better work-life balance.
The professions of others are more enticing. If your friends or family members have jobs that interest you more than your own, it may be worthwhile to look into them.
You desire a job that allows you to pursue your interests. Your present employment may not have been your first choice, but switching occupations might help you discover more meaningful work and advance in your career.