Answer:
Gets rid of bad ones, short and tall. Tightens when used, one size fits all.
Half-way up the hill, I see you at last, lying beneath me with your sounds and sights. A city in the twilight, dim and vast, with smoking roofs, soft bells, and gleaming lights.
What always goes to bed with his shoes on?
I cost no money to use, or conscious effort to take part of. And as far as you can see, there is nothing to me. But without me, you are dead.
You can hold it without using your hands or arms. What is it?
If itβs information you seek, come and see me. If itβs pairs of letters you need, I have consecutively three. What am I?