On
888 Poker deals are based on ICM, and the only choise for players is to accept or decline the numbers, which are calculated by 888 Pokers computer. I have regularly accepted deals when heads-up or 3-handed if:
1) I felt, that I had no obvious skill edge on the opponent(s)
2) The payjumps were significant to my bankroll
3) I wanted to end my session to get on with other tasks
As for point number 2 a reasonable way to look at it is, that if you are playing for a payjump of 100$ heads-up, you should be bankrolled for a 50$ heads-up SnG. Like maybe having a bankroll of 2.500$ (50 BI) or at least 1.500$ (30 BI). If you dont have that, then declining a deal means, you are taking unnessesary and unreasonable swings to your bankroll.
As for point number 3 it should be noted, that on
888 Poker money is not set aside for the eventual winner. So once a deal is made, players are basically only playing for the title, and its customary, that both players go all in preflop every hand, until its over. For me this has often been a main consideration in accepting deals. If I have already played for 7-8 hours, I am typically not in the mood to spend another 30-60 minutes on, what is essentially a 3-handed or heads-up SnG.