Hana

Ours was six sashes and one large room replastered, done by two different trades. The windows were out of the house for about three weeks in a workshop, which nobody warned us about, so we lived with boarded openings and it was cold and dark and grim. The plastering was four days of work and about three weeks before it was ready to paint. So the working days were maybe fifteen and the calendar was closer to two months, and the two months is what you actually experience.

Replace the slider. Squeezing works because it temporarily narrows a slider whose channel has worn wider, and the metal springs back or wears again within days, which is exactly the pattern you're describing. A new slider of the right size and type costs very little and takes about 20 minutes. You need the size number, usually stamped on the back of the old slider, and you need to know it's a coil zip rather than moulded, which it sounds like you do.

It works, just make it dense and use a strong thread. A weak stop and the slider comes off in the rain, which is a bad day.

Size 5 coil, plus whether it's an autolock or non-lock, plus single or double pull. For a jacket you probably want autolock. Buy a couple, they're pennies and the first one always goes flying across the room.

If your pack has side compression straps, cinch them after everything is in, not before. Pulling them at the end squares the load off. Half the people I see at the gate have theirs hanging loose.

Four inches is past where the original hem method behaves. That technique works well up to about two inches because the folded excess sits inside the leg without much taper mismatch. At four, the leg opening at your new hem is meaningfully narrower than the original hem circumference you're reattaching, so you either get puckering or you have to ease it in and it looks wrong. I'd cut, then rebuild the look: sew a new hem and topstitch with a heavy gold thread in a triple stitch. Not identical, but deliberate.

Topstitch weight, roughly 30 to 40, in the needle only, regular thread in the bobbin, and a jeans needle at 100. Lengthen the stitch to about 3.5mm.

One thing to check while it's still fresh: how far past the thin area you took the darn. A common first-darn mistake is repairing only the hole and not the worn halo around it, which feels fine now and then goes through in a ring around your lovely patch. If the wool around the mend looks thinner and shinier than the rest of the sleeve, extend the darn out into it.

It works far better with wool or a wool blend than with cotton. A cotton tee is done after one warm day and it takes forever to dry, so if you're set on two shirts, make at least one of them merino. Socks and underwear are where I'd never go below three, since those are cheap, tiny and unpleasant to get wrong.