I did until ds was about 6 weeks old. My hv told me I ought to when they're really newborn as they don't always wake themselves up if they're hungry. One other thing that would concern me at the moment is the warm weather, so if it were me, I probably would wake your ds up for a feed.
if during the day no, definately, I used to and ALWAYS had a grumpy upset tired baby on my hands! if night though I would check nappies, my DS always woke when he was hungry but I did have a friend with a very sleepy baby and in the 1st 3/4weeks she did wake him every 5 hours at night
During the day when DD and DS were little I woke every 3 - 4 hours to make sure they got enough feed in them that they weren't waking so often at night. Although it's great if they sleep well and give you a break (my DD did - it was marvellous) in the day if you find they're waking up a lot at night to feed you might find waking during the day a bit might help that. They do settle down as they get bigger though and sleep and feed less and find their own pattern - at 2 - 3 weeks things are still very up in the air.