Last week I wrote Why I use WordPress.com not WordPress.org.
It comes down to making life simpler. One aspect I forgot to mention was the free WordPress.com service gives me 3GB of storage. That means an unlimited number of posts and an unlimited number of images.
When I used a paid hosting service and WordPress.Org I twice had to upgrade my account with extra storage to cope with the number of posts – there are nearly 1000 – and images. And when the space began to run out, the site would slow down.