Obligation Of Wuddu
Urination, Defecation, ejaculation, coming out of pre-seminal fluid, and passing of wind, invalidates Wudu. During Sleep one is not aware if his Wudu is intact, therefore it obligates to make a new wudu. If someone does not remember the state of his wudu, he should make a new wudu.
If someone does not remember the state of his wudu, he should make a new wudu. By “should” do you mean it is recommended or a must? It is easy for me to make wuddu after waking up from sleep but difficult remembering if I broke wuddu during wake times or not