Hana

Eggs survive perfectly well in a wardrobe over winter. Assume they haven't moved on.

Deal with the moths before the holes. If they were live, everything in that drawer needs 72 hours in a freezer in a sealed bag, or a hot wash if the garment can take it, otherwise you will be doing this again in three months on a jumper you've already mended. I lost two good sweaters learning that.

A zigzag on a heel gives you a dense stitched slab with even less stretch than a hand darn, and it tends to tear out at the edges after a few washes. Fine on a woven patch, not great on ribbed sock knit.

Also check where you're anchoring. If you start and stop the rows right at the edge of the hole, all the bulk lands in one ring and that ring is what you're feeling. Spread the anchor points over at least 1cm of healthy fabric all around and stagger them so no two rows end in the same place.

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.