You don’t need one to do most projects but they can be very useful. I’ve used mine twice today, once for cutting out a hole for a plug socket in a plasterboard wall and again to cut a skirting board attached to the wall so I could remove one section without taking off the whole board. Could I have done this with other tools, yes totally, but it makes jobs like these so easy and quick. I’ll probably use mine in most projects I do around the house, so would recommend, but I went for years without having one and it was never an issue, you just use other tools. I chose to get a battery impact driver and drill before my multi tool and never regretted that decision. Tldr, nice to have but not a necessity.