I haven’t done houseplants for years but I would think much depends on the types you have. Cactus or moisture-lovers, something in-between? 

I’ve heard of piling all into the tub with enough water to keep them wet for just so long, like half the time you’re gone and then they’re ready for a drink when you get back. Or covering each with a bag or other translucent object that can act as a terrarium preventing moisture loss. There are a bunch of DIY videos online, too. Water-wicking, that sort of thing.

Or you can go for intricate watering systems with tubes to each plant. Electronic sensors, etc.

Kitty

I always found the best thing was a 10-year-old neighbor.