Are sliding miter saws necessary?

If most of your planned projects involved making picture frames or cutting baseboards and moldings to size, a compound miter saw is all you need. That said, if you plan to work with material 8-inches across or wider, you'll need sliding miter saw for quick and accurate results. One more thing to think about is space.

Read remaining answer here. Furthermore, what is the advantage of a sliding miter saw?

They can quickly create bevels at any angle. Sliding compound miter saws have all the versatility of compound miter saws and a sliding feature, similar to a radial arm saw, allowing you to move the blade forward and backward. The major advantage of the sliding feature is the increased length of cut it provides.

Additionally, do I need a Mitre saw? Miter saws are (obviously) great for making quick and accurate miters (like 45-degree angles for picture frames), and they're also very efficient for cross cutting small pieces of material like trim (molding, baseboards). That makes them completely incapable of ripping boards to width (cutting them lengthwise).

Moreover, what is the difference between a compound and sliding Mitre saw?

The main difference between a sliding compound miter saw and a compound miter saw is the rail or rails on the sliding saw. These rails allow you to slide the saw back and forward as you cut. The saw can do everything that a compound miter saw can do. This makes cutting thick materials like fence post much easier.

Should I get a 10 or 12 inch miter saw?

Trim is seldom more than 4 inches, so you've got plenty of wiggle room with a 10-inch miter saw. A 10-inch blade will spin faster than a 12-inch blade, resulting in smoother cuts. Equal motors powering the two blades will result in a higher RPM rate on the 10-inch blade and higher RPMs mean a finer finish.