Is it necessary to power-stretch when installing carpet

In a normal room-sized install, both tools are used. The kicker for the first edge and the stretcher for the rest. Kickers are also used in corners where the stretcher is awkward to use. On stairs, just a kicker is used.

• A kicker is ideally only used to attach the carpet to the tack strip.

• A stretcher is used to attach the unanchored sides. You anchor it at an attached side and stretch the carpet to the opposite side.

A pro would use a stretcher as much as possible. A carpet that has been kicked with a reasonable amount of effort will pull up at the edges from any typical abuse.

A small space like 2x3 would have only used a kicker - which is why they invented the mini-stretcher (like this one). They're not cheap for a single job and I haven't seen one for rent, but it's worth a few calls around.

That's not to say you can't just use a kicker, and I probably would if I didn't have access to a mini-stretcher. You can do a 90% job in a small space with a kicker, but you'll definitely work up a sweat.

FYI: For larger jobs, even with maximum effort, the smaller head of the kicker will lead towards ripping the carpet if you try to get the same amount of stretch as the power stretcher will give you with no effort.

Nope, your carpets weren't installed correctly. I'm not sure if code dictates that tack strips need to be replaced, but at the minimum, your contractor should have checked if any tacks were poking through or would otherwise pose a needle hazard. Those things hurt.

Shedding seems to be normal. We recently had some carpet installed on our basement stairs, and some corners (and manually-cut straight edges) do have the little plastic strings hanging loose, and several nylon curlicues roaming around. I really wish all installers would properly vacuum their junk up, but most of them don't.

Carpet on the steps does not necessarily have to be a single piece, simply because you can start a new piece (and stop the old strip) where a tread and riser meet. As long as the edges are butted together with no gaps, you should be fine.

Also, simply vacuuming should not lift carpet edge off (anywhere, specifically not stairs!)... that alone should require that they come back and fix it, or pay for a professional to re-do the effort.