From the remembrances of the day and evening is his statement
سبحان الله و بمحده
100 times in the morning and evening. Is it restricted to this number or is it permissible for him to increase since he increases and decreases sometimes?
The answer to this is that the increase in it is an increase in rewards. The prophet صلى الله عليه و سلم said in the narration
مَنْ قَالَ حِينَ يُصْبِحُ وَحِينَ يُمْسِي سُبْحَانَ اللَّهِ وَبِحَمْدِهِ مِائَةَ مَرَّةٍ لَمْ يَأْتِ أَحَدٌ يَوْمَ الْقِيَامَةِ بِأَفْضَلَ مِمَّا جَاءَ بِهِ إِلَّا أَحَدٌ قَالَ مِثْلَ مَا قَالَ أَوْ زَادَ عَلَيْهِ ).
“The one who says when he wakes up and the evening enters ‘Subhanallah Wa Bi Hamdihi’ 100 times, none will come on the day of judgement with better than that which he has come with except a man who said similar or increased upon it'” [Agreed upon from Abu Huraira, may Allah be pleased with him]
So if he increases, there is no problem. It is permissible to increase and say it 100 times for he will attain the mentioned virtue
“except for a man who says similar or increases upon it”
Majid Jawed Al-Afghanee