If you're using a handsaw and find that a board you have just cut is 1/16 in. or 1/8 in. too long, here's a way to re-cut the board without making a mess of things. Find another board the same width and clamp it over the top of the board you want to trim. Then mark the cut line on the top board and make the cut. The kerf of the top board will keep the saw in line for a perfect cut below it.
Once you have invested in quality power tools, follow through with premium blades, bits or accessories to take full advantage of high-quality engineering. For example, if you try to get by with a cheap saw blade instead of a premium blade, a saw will not perform up to its potential no matter what you paid it.