Are you new at forex?
I ask since you say you�ll see then how it goes�. 
Regards!
Nowadays I actually watch something like 22 pairs and it isn’t a problem at all since I search for patterns. Flipping through the charts is fast.
I normally watch around 10 - 12 pairs but normally just stick to trading the major ones. I don’t like trading those wacky crosses - the spread is just too crazy haha
I trade the 4 majors and 2 local pairs - USD/JPY and AUD/USD.
I trade these on 9 different time frames each - plus a 5 minute chart of each.
That is 60 charts simultaneously.
But Dealbook handles that no problem.