Limited well-lit space for my plants is an issue in my urban apartment, so when I transplanted the spiderettes that were rapidly outgrowing their small pots, I combined them into one container as one plant to save on valuable sill space. You can do this with many different plants, not just spider plants!
There’s no one right way to start seeds. Seed starting is as personal and diverse as gardeners themselves. But if going to the garden centre and buying seedlings that are ready to plant is so easy… why do I commit to the time and energy it takes to grow from seed?