I bought most of my firsts clothes second hand, and wear a lot of second hand myself. I saved everything from my first - she’s 3 now and I’ve had to start being more selective about how much I keep to pass down because there is just so much! If you think about how much you have put away now if your eldest is 18 months, that will have basically doubled again at age 3 - they are in one size for longer but I find that means you end up with more, especially when you need lots of spares for nursery/potty training. You also need things for summer then winter etc. We have a lot of storage in our house but the amount of space it takes up is unreal and it’s a nightmare sorting through it all to find the right size.
We may have another baby or two after my second, but I’m being ruthless about what I keep. As I’ve got things out for my second, I’ve been surprised but how battered a lot of it is that I thought was fine when put away. Little holes emerging at the edges of poppers, stains that I hadn’t noticed, colours looking really faded etc. While my eldest wore second hand I only bought things in great condition, and would restore anything that looked tired myself or get rid, so I wouldn’t put baby in stained clothes. I felt really embarrassed at a baby class this week, when there were lots of first babies there dressed immaculately in little outfits. My baby had a little sleepsuit on, because I love them in a sleepsuit when they’re tiny, but I looked down and realised there was a rip by the popper and worried that it just seemed like I didn’t care.
Also I’ve kept so much I really can’t justify buying anything for second baby and love it when I do choose a few bits. I do try and maintain things nicely - I have a debobbler which I use on anything that gets bobbly. I manage to get pretty much any stain out except paint. I wash things on a long 40/60 eco wash, with any stain remover powder, normally the own brand supermarket ones. I use washing powder and make sure I’m using enough - I weighed one full scoop of the scoop I use and realised I’d been using about half of what was recommended on the box. That gets most things out - whenever I use a shorter 1.5 hour cycle I find half the stuff comes out still dirty. I also soak things in napisan (for colours) or Milton (for whites) with water from the kettle in a bucket. That gets out really tough stains even if they’ve been washed and dried a couple of times since. The sun is also brilliant for anything biological - food, poo, dirt etc. it just lifts it straight out.
If I’ve done all that and it’s still stained I donate it to charity in a rag bag. I know what you mean about cost, but you can buy bundles on Vinted or Facebook really cheaply - I’ve had a bin bags worth of clothes from Facebook for £10, and they were all next/jojo etc and in great quality the lady just wanted to be rid of them and not have to list individually. So knowing how cheaply I can pick things up, I don’t send her in stained things. If you’re washing things long and hot enough with enough powder and stain remover you shouldn’t have many stains anyway.