[simne]

BTW, few things from professional exp:

1. Cheap components (most probably you will use such in 99% cases) are +-5% from claimed parameters (sometimes appear batches with more than +-10% difference). Also, unfortunately, cheap components parameters changed very large with temperature and when high voltage applied (100V is enough). And yes, I all time have ready measurement tool near, and always first check component parameters when something not working.

2. Experienced developers when considering batches, trying to make designs, which tolerate more than 10% difference of parameters, and just buy few reels with near to magnitudes numbers which fit in all circuit. For example, 1KOhm, 5KOhm, 10KOkm, 100KOhm, 500KOhm.

3. Just few times in my whole life, I seen very expensive precision components, like 0.5Ohm 5W for high-end audio. This one resistor costs somewhere about 5$, but it is only one in whole circuit.