When I need to enter formula values, which are given in percentage(e.g. 3%), I always almost enter them in decimal (e.g. 0.03), which has worked but I do feel that at times I can just enter values in percentages and dont have to do the extra effort of first converting the input values to decimal and then convert the answer back to percentage.

Is there a rule of thumb, when we should enter values in formula in percentage vs decimal?