That is always difficult. It requires a great deal of reflection and self inventory. Generally I personally boil it down to the questions of "Am I doing this solely for my own personal benefit? Or, am I doing this for the benefit of others?" If I am truly honest about these questions, most of the time even when I do for others, the need for recognition still crops up. I can't seem to entirely shake that. In regards to service of the Divine, I try and never say "no", to reasonable requests. Someone needs my help, I show up. Service to others is the ultimate service to God. At the end of the day, as humans, we just want to feel useful to the people around us.