Me myself I love the informal look. I think, like a cottage garden. Well in my mind its a cottage garden type

I like the formal look to but just not as much.
I just put plants I like together, and if I don't like it that way I'll move them. I never make plans for a flower bed, except for the shape, and sometimes not even that LOL.
I know I have to many plants in one spot, but then I don't have to use mulch in that particular bed

In some beds I do use mulch, in the ones with out a lot of plants. The ones that don't do good all squished in together.