The eminent Muslim scholar and renowned Da`iyah, Sheikh `Abdel Khaliq Hasan Ash-Shareef, states: “One’s wudu’ is correct if they did the obligatory acts of wudu’. However, we advise muslims to realize that man may commit sins that need more good deeds to remove them. In case of the man who is doing only the prescribed acts of wudu’, Prayer, Zakah, etc. he is supposed to do all prescribed acts completely and to abstain from all prohibitions.
So, there is nothing wrong in doing only the prescribed acts of worship as long as one does them well and abstains from all prohibitions.
Here it should be noted that among the virtues of sunnah or nafl acts is that it removes sins and compensates for any shortcoming or incompleteness with regard to the prescribed acts of worship. It was reported that the first thing man will be asked about on the Day of Judgment is Prayer. If it is incomplete, Almighty Allah says, “Does My servant have nafl acts.” If he has some, they make up for what is incomplete with regard to the incomplete prescribed acts of worship.”