does increasing credit limit affect credit score

Yes, increasing your credit limit does affect your credit score. A voluntary request for an increase may cause a temporary, small drop due to a 'hard inquiry' by your bank. However, the long-term impact is often positive. A higher limit decreases your credit utilization ratio—the amount of available credit you use—which is a major factor in improving your credit score, provided you maintain your current spending levels. Automatic increases usually do not impact your score.