Buying New for #3?

I am pregnant with our third baby. I already have a 4.5 year old and a 3 year old and all of our big items are from my first born, so five-ish years old. While we don't NEED anything there are a few things on the market now that would make things easier. For example, we have a really heavy infant carseat. It didn't matter when we weren't running around much with my firstborn but my kids now have school, sports, ect. and I'm considering a lighter one. We would also need a new stroller if we get a new car seat. However, this is probably our last and I'm not sure it's worth it. We also have a swing that still works but it's HUGE. It was fine with with one kid, even a toddler and a newborn, but with older kids (and a 100 pound dog) things are already feeling crowded so I'm consider a Momaroo. Would you buy new if you already had these items if it made things more convenient?