A short word on resistors. There are two common kinds available. The brown (carbon film) and the blue (metal film) ones.

The metal film resistors are generally preferred for the following reasons:

• They have a smaller tolerance (1%) compared to the carbon film resistors (5-6%). That means that the actual resistance is very close to what it says on the box. In contrast the carbon film resistors vary a lot more. A 100 Ohm carbon film resistor can have an actual resistance of only 88 Ohm which is quite a difference.
• They can handle more load than carbon film resistors while getting not as hot. (0.6W compared to 0.25W)
• They produce less noise. This is not that important but still its a benefit

I mention this because initially I bought two boxes of the brown ones and I didn’t know about the difference. The advantages are not big enough to throw away all my carbon film resistors as they still work but I prefer metal film resistors from now on.