Actually OP, I've been thinking about this over settling the non-sleeping baby.
Whether or not you need one/will get your money's worth, depends on your lifestyle and where you live. I read people saying they just carried a few nappies and wipes and I thought "how to you cope all day with just that?" and then read more that actually, they drive everywhere and have all the additional stuff in the car, or others just don't seem to go out all day.
Rather like the whole buggy issue (which if you haven't tackled yet, good luck!).
For example, I often read on here that "everyone" ends up getting a Mclaren/umbrella fold after 6 months and stops using the big buggy. However, that's not been my experience in this town. I was given an umbrella fold when I went on holiday and I couldn't work out how anyone copes with something that's so hard to push with little wheels, if you put any sort of weight on the handlebars it tips backwards, and you have to if you're out for a long day as the basket is tiny. I thought it was a stupid waste of money if you already had a travel system, to buy something extra that's lower quality.
I mentioned it to one of the few people I know who uses one, but she explained it was easy to fold for the car boot. and I realised, she lives a lot further out than me, I live 25-30mins walk from our town centre, so I walk to town if I want to go to the shops, I need something I can easily push up the hills to the town, she needs something she can drive to town and so needs somethign to fold up and pootle around town with. I only really take the car to the supermarket, so I stick the carseat in the shopping trolly and don't bother taking the buggy. I also have a parade of small shops near me, so for 'basket' shop (rather than weekly big trolly shop), I'll go there and need a decent sized basket underneath for the shopping, she has to go to the supermarket as she's no small shops in walking distance, but she'll take the Mclaren rather than use a trolly for a small shop.
I have a wide hall at home so can leave the buggy set up in there and still get past (I can go weeks without folding it), she doesn't so has to fold the buggy all the time it's not in use.
Baby monitors are another one that may or may not be 'vital baby kit', another friend didn't understand why anyone spent any money on one, but she lives in a flat where the baby's bedroom was just off the living room so she could easily hear her DS wake up, in our house you can't hear DD cry in the front room if the doors are shut, so we needed one.
So very long post, but basically, it's no good you asking anyone for their opinions on what is and isn't worth it for baby related stuff, because depending on your lifestyle, transport, home layout, how you feed, if you use reusable nappies or not etc will depend on how useful something is to you.