No one can answer that question but you, Eurotraveller. For myself, when I'm paying, I have a six hour rule. More than six then I travel PE/WT+. I have always considered it worth paying and regularly choose to pay for PE on long haul. Indeed, I would only travel Y on long haul if something VERY serious demanded me to be there!
Some folks prefer to spend more on hotels/clothes/etc. I choose to ride more comfortably on aircraft. In March I did LHR/JNB~CPT/LHR in PE and paid about double what I would have paid for Y and was happy with my choice. Some of my friends think I'm crazy.