Thanks to all for their valuable update.

So what I understand is Differential backup is important but not hard and fast. What is important is your log backup must be at regular frequency as per your database size which will not only help to minimise the log file space on drive but also smallest the file, quickest to resote 😀

Also if required apply differential backup if full backup is taking too much cost of disk I/O and taking time...:w00t: