My preferred solution is a primary pump with battery backup, and a secondary/backup pump that is set at a slightly higher fill level than the primary. The primary covers it most of the time, and the battery will keep it going through short outages. The backup pump covers it if there is complete failure of the primary pump. I have this setup, including a one-way Y fitting so that both pumps can exit through the same pipe.

Do you know where the water enters the basement? And how old is the house? Many water problems can be resolved with regrading around the house, downspouts with a long exit pipe away from the house, and other simple changes to keep water away from the foundation or route it through other paths in the yard.

However, in an older home you may need a basement sump pump if the water is coming up from under the slab, like a rain-driven spring. Concrete floors are porous, and in older homes they did not put plastic sheeting or insulation down before the pour. This means there may be hydraulic pressure pushing water up through the slab.

Bruce

I have the same setup as Bruce ^ and I'm in a wet location. Runs constantly in the spring, and I've lost power before so I'm happy I had the battery backup.

My neighbor has 2 sump pits at opposite ends of his house - he says one runs a lot (like mine) but the other doesn't run at all. Another neighbor has an "oversized pit" with just a battery backup, without the higher backup pump. Another neighbor has 2 normal pits right next to each other, either with any type of backup. I guess there is more than 1 way and multiple ways will work

#1 thing to do is everything Bruce already said. Pitch your landscaping/yard away from the house, and make sure your downspouts are dumping water as far away as possible. My parents old house started having water accumulate in the basement after it was 30 years old - turned out the landscaping sunk so it was pitching water into the house foundation. Also they never cleaned their gutters, so years of them sitting full/heavy bent them away slightly, so roof water would come down the drip-edge flashing and fall straight down behind the gutter and never make it into it...