A drip system is costly, no one has the time to water their plants by hand daily, (plus the chances of us doing so systematically like plants need it - is unlikely), and dowsing our plants in water hoping they will naturally spread out their rations is unlikely.
Have you ever heard of wick watering? By wrapping the potting soil at home, or lining your beds with wicks (Or using shoe laces, yes SHOE LACES), anchored to a tub or reservoir of water of some type (milk jug, coffee mug, water bottle ect); your plants will take whats needed when its needed. Allowing long term vacations. I havent tried this myself yet; however, one gentle man has and tried this on a larger scale.
Read his how-to and his product results for out door wick watering
For much smaller gardens, like single pots or indoor plants:
A tale of caution, do not use cotton; it will cause root rot. Use nylon.
Some people struggle using this method.... here are some tips and tricks and some trendy inventive alternatives with polyester.