if cell i is not enpty then enter "text"or data in cell m and count

hi
i have a spreadsheet with data with collumns a to q and rows 3 to say 30,not sure if all can be done with conditional formatting or macro
what i would like to achieve is ,this is a stock take sheet,if cell i has data in in it then populate cell m with a number 1,when this item is used and returned the number in cell m should increase by 1,so at the end of the month i can see how many times this item has been taken out and returned,if no number it has not been issued, i already have code to highlight empty rows, its just if cf can enter numbers in cell or vba the way to go,any pointers would be good have read that many threads today my heads spinning
cheers colin