Sleep transitions?

Hello parents! I believe my 4months plus LO is in sleep transition recently. She wakes up more in the middle of the night (sometimes not for milk) and stays awake (can be awake for more than 1 hr). She fusses a bit and never cries, should I help her to fall back asleep or let her be in the crib? During daytimes, she tends to nap longer. She can nap more than 3 hours sometimes, should I wake her up from her nap? 3 hours seems a bit too long for 1 nap?