Why shouldn't you use a splitter?
Because there's no such thing as a free lunch. Or, if you're into physics, remember that Leibniz proved that the amount of energy in a system remains constant.
What does that mean for you? It means that if you split your antenna signal using a 1x2 splitter, each TV gets a signal half as strong. If you use a 1x8 splitter, each TV gets a signal only 12.5% as strong as the original. Because you can't split a signal without losing something.
Oh yes you can use an amplifier to make up for losses, and that can help to an extent. And it helps too that it's not all as bad as it sounds to lose half the signal, which is why we measure signal in things like "dB" which give you a better idea of what you're losing. It sounds a lot better to say that you've lost 12dB of signal than to say that 87.5% of the signal you had before the signal is now gone.
And that's the whole point when I say that you shouldn't use big splitter if you don't have to. Even though amplifiers help, they also hurt (which is a topic for another day.) The best thing to do is to keep as much signal as possible without needlessly splitting it. That's how you get the best result.
There's no getting away from this simple fact either. If you think that you're better off with a 1x8 splitter than with two 1x4s and a 1x2, you're mostly mistaken. You're probably a little better off because each one of those components have what's called "insertion loss" meaning that you lose some signal just by connecting them, but it's not a whole lot.
The bottom line here folks is that a little bit of planning can make a big difference. Rather than simply tacking another splitter on, replace small splitters with large ones, or even better try to figure out if you really need that large splitter. Plan accordingly and you'll always find that you'll get the best possible quality from your antenna, dish, or cell repeater.