Torah's Hashkafa re ending life

Quality of life
 The Ran in Meseches Nedarim (40a) says , If a sick person is suffering and he won’t get better, it is proper to Daven for this person, to die. 
As we find in the Gemoro, the maid of Rebbi saw how difficult it was for him to remove and put on his Tefillin every time he used the washroom, she Davened that he should die.(Kesuvos 104a). 

 The Yalkut Shimoni (Devarim 11 :871) writes , there was a woman who went to R. Yosi b. Chalafta and complained she was old and fed up with life. Her food and drink have no taste. She wants to die. R.Y.B.C. asked her what good deed, does she do. She answered that she gets up early every morning and goes to Shul. R.Y.B.C. advised her to stop doing it and within 3 days she died. 

 It seems, not tasting food & drink or having to put on and remove Tefillin numerous times a day, is considred suffering and enough, to Daven for that person to die. 

 On the other hand, we find Mamorei Chazal, that suffering in this world has its benefits. We also find every minute alive is precious and one may be Mechalell Shabbos to extend life even for a short period. How do we reconcile with these conflicting Mamorei Chazal?