My son is 2 (very recently) and I'm due another baby in 6-7 weeks. We still use a monitor for our little boy as he wakes in the night and murmurs (doesn't actually call out for us). We need to get another monitor for the new baby soon .
Stupid question but can you use two monitors in the same house? Our home is quite small at the moment so the monitors will be close to each other iyswim?
Does it make a difference if you use the same brand or is it better to use different? 
I know it's probably a daft question but does anyone know? Thanks