How do you know what tools are needed for projects and which brand?

Some are a lot better, but unless you are a pro, you can watch price, When I first started 50 years ago I got better tools. Now I don't do as much and I tend to go cheaper. I am a fan of Black and Decker. They serve me well for small projects.

Every home should have a battery operated drill or cordless screwdriver... the saws will depend on the type of projects you do... and a small palm sander can come in handy... the brand is all due to personal preference... We have Black and Decker Firestorm... and they have worked well... but there are other brands that do just as well... check the reviews... and look for sales on the "combo" power tool sets.... sometimes (like Christmas and Father's day) you can find some really good deals.

Cordless is the way to go for most power tools. I am a fan of Ryobi's One+ line. Been using them for years and they have improved the batteries a lot. Home Depot sells them but you can get a kit with a lot of different tools for short money on eBay.

Most big box stores sell kits of tools. They generally include the most used or handiest ones. Those kits take most of the guess work out of this for you.