When doing electronics design work, you work within certain tolerances which could be as tight as 0.1% and loose as 200%.
You learn when a tight tolerance is important and demanded.
In many cases, capacitance and resistance within 20% is acceptable.
For a 800Ω resistor, you choose the nearest value above or below, 750Ω or 820Ω. even 680Ω might be acceptable.
Then you learn whether it is better to go high or low, depending on the application and the desired effect.
Let your knowledge of electronics guide you. It will come with time and practice.
You learn when a tight tolerance is important and demanded.
In many cases, capacitance and resistance within 20% is acceptable.
For a 800Ω resistor, you choose the nearest value above or below, 750Ω or 820Ω. even 680Ω might be acceptable.
Then you learn whether it is better to go high or low, depending on the application and the desired effect.
Let your knowledge of electronics guide you. It will come with time and practice.