Glad to hear we’ve been helpful!
Sorry for this long post, but the OP asked for A-Z advice. If it sounds like I’m giving a sales pitch, it’s because I am in sense, but I have no vested interest in your purchase whether it’s from Home Depot or a premiere carpeting store (which I worked at).
Here are some tips that can help save money and probably get a better experience with the salesperson and estimator. It’s been over 10 years since I sold flooring, but little if anything has changed since then.
Carpet width - is usually 12’ or 13’ 6". So measure both dimensions of your room (you can sketch it out to help visualize better) and do a rough estimate of which width would fit the majority of the areas better. If they’re multiples of 12’ or less it may be better look for 12’ width (it may be marked on the sample) to minimize overage and seams (more about this below). Carpet when stretched can add an extra inch or two, so if one dimension is within an inch or two of 12" or 13’ 6" you’ll be fine estimating with those widths.
Keep in mind that all carpet has a grain or sometimes pattern that will affect how much s required. The grain is most noticeable in daylight since it’s full spectrum and hits the carpet from all angles. You many not notice the grain (i.e. the way the light reflects off the carpet changing the color) with indoor lighting, but will with sunlight. It’s not noticeable with small areas or samples. The best example I can think of of a field of wheat being blown by the wind in one direction and you’re looking at it from overhead. All the stalks are leaning one way. Now imagine that you take a section of that field and rotate it 90 degrees without the stalks changing direction. That’s grain (no pun intended) and you’ll see a noticeable difference where the two sections meet.
Seams - A good estimator and install crew will try to keep seams to two or three max per room. Seams are weak points and should be kept to a minimum, especially in high traffic areas like entryways and hallways. It takes more carpeting, but a good estimator and installer crew (more about this below) will try to lay the carpet in a hallway in one piece vs multiple seams along the length since it’s a high traffic area.
Using more seams = less carpet required and this is one of the sales tricks that may allow a store/company to get a lower estimate. I worked for the premiere carpeting store (A franchise of a national chain) and we were the most expensive in the market. However, that also meant we strived to provide the best quality install even if it meant more carpeting.
Estimator and install crews - As mentioned in my thread above, a good install crew will follow the estimator’s layout closely. At the store I worked we had both in-house estimators and installers that knew each other’s work. Sometimes if a job was difficult, for example an odd shaped room, the estimator would specify a certain experienced installer or crew. One person can easily do a single room or up to a certain amount of carpeting (I forget, but maybe 5-600 sf?) themselves, but larger rooms and areas requires more people because the carpeting has to stretched in directions.
As I stated above, the store I worked at was top of the line in our area and that’s why we had our own in-house staff. However the owner also had a companion store that focused on cost savings. This store had their a list of recommended independent estimators (some of the salespeople did their own estimating) and a bulletin board with cards from independent installers. I believe this is also how places like non-specialty carpeting/flooring stores like Home Depot do it.
I’m not saying it’s necessary to shop at the a specialty flooring store, but be sure to ask for strong recommendations or possibly references if you’re going to use independent estimators and installers. Maybe use Angie’s List for reviews.
Carpet grain and type - I think I explained grain pretty clearly above. In a nutshell, all the carpet should be laid in the same direction. If a piece is installed at 90 or 180 degrees, you’ll see a difference in the color and shading of that piece, especially in bright sunlight.
As for type, there are three main types of carpet: cut pile, loop and berber. All carpeting is woven with loops. If the top of the loops are cut, it becomes cut pile. The more and closer the loops, the softer and plusher the carpet feels. Another advantage to cut pile is that if you snag a tuff, you’re unlikely to pull the entire line woven line out.
Loop is the uncut threads. The carpet won’t feel as plush and soft, but will wear better because the cut ends of the tuffs aren’t exposed. You’ll also get less fuzz balls, especially in the begining because there’s less loose threads. However, if you snag a loop and accidentally pull on it, you’re more likely to pull a length of loops out. If you have children or move a lot a furniture or other things around, I reccomend against loop carpeting.
Berber. This is the tightly woven, usually lightly spotted carpeting. It’s much firmer than plush and loop carpet, but it wears well because of its heavier construction. Its tight weave and heaver material makes it harder to snag and unravel, but once you start a run, it’s harder to stop and it’s more noticeable. If you get a snag and run in a berber or loop carpet, put a few drops of super glue at the start of the run to keep it from unraveling.
Padding - Get the best quality and (generally thickest) padding you can, but don’t overbuy. Do spend a bit more on the best quality padding you can since it will only only make the carpet feel better underfoot or under body if you lay on it like I do, but it will help preserve the nap (the threads/loops) of the carpet because it acts as a cushion. Don’t buy the multicolor padding. These are made with scraps of different types of padding and will have hard and soft spots that can cause uneven wear on you carpet and just feel bad.
Product naming - I used to get a little chuckle when customers would say, “This looks and feels just like carpet <name> does at store XXX.”. I was a too honest saleperson and explain to them that it may very well be the same product or if was at our sister store, was the exact same carpet just with a different name and since it was from Stainmaster, had different warranties with ours costing more because we had the top of the line warranty. On the other hand, just because a carpet may be named the same or look and feel the same, doesn’t mean it’s the same thing. Look between the tuffs/loops of the carpet and while it may look and feel the same, the lower priced one may have fewer loops = less material.
Nylon and polyester - are the two main types of carpet fibers. Both may look and feel the same in the showroom, but nylon carpets will wear better and last longer before the nap becomes crushed than the cheaper polyester. I had a regular customer who owned an apartment building whose tenants were primarily college students so they usually didn’t stay more than 2-4 years. He’d always buy cheap polyester carpeting because it was cheaper and easier just to replace it than cleaning it after the tenants left.
There’s lots more that can be said, but these are the (probably too long) basics.
