Not only do you need a breath of fresh air every now and then, but some plants also feel better after spending some time in the open air. A warm sun on their green orb or the gentle breeze through their leaves are real boosts and ensure that they can get on with their lives indoors for a while.
Most plants originate from a place far from the cold Netherlands. They grow in a warm desert or a moist rainforest. They find more or less the same warmth in our living rooms, but they lack the other advantages of living in nature. With us it is sometimes really surviving in those dry newly built houses, especially in winter. That is why being outside for a while is very nice for a tropical houseplant: a real shower of rain instead of a spout from the watering can does wonders.
A sprinkling or a shower will make some houseplants feel better immediately. By watering, you increase the humidity and mimic the living conditions in the tropics. Is it 15 degrees or higher outside and do you see on Buienradar that rain is coming? Then you can put plants outside that you normally water. Rainwater they find much tastier than our tap water.