Short answer: in almost all cases high accuracy is not required unless specified otherwise in the bill of materials or schematic. Most builders are using 1% tolerance resistors up to about 1W, except in the most critical of uses, and high wattage resistors are usually 5% or so.
Longer answer:
There are several factors to consider.
A "7K" 1% resistor could actually be between 7.07K and about 6.93K and still be in spec. Similarly 4.2K could be between about 4.24K and 4.16K and still be labelled as 4.2K 1% resistor. So if you are lucky with your 4.22K and 6.98K resistors they could fall within the specs of the 7K and 4.2K anyway.
If you have a good LCR meter or multimeter you could buy multiple resistors, measure and hand select the closest match to the values you want. But this is usually not necessary and requires a highly accurate measuring device.
If you need accuracy without measurement you can go for 0.1% parts but they cost more, typically don't come is as wide variety of wattages and often have lower voltage ratings.
Also consider that all resistors heat up when current passes through them and the heat changes their resistance. The amount the resistance changes depends on the materials and manufacturing of the resistor and is usually specified in ppm per degree of temp rise (lower is better i.e. more stable but also more costly). Unless the use of the resistor in the circuit is critical, around 50 to 200ppm is fine for low wattage resistors and multiple hundred ppm is common for higher wattage... So in circuit, depending upon the power the resistor is dissipating, its resistance will vary from that measured when cold anyway...
It is vital you don't exceed the voltage or wattage rating of a resistor and it is good practice to operate them bellow their ratings for safety and long term reliability. When looking at the voltage rating look for working voltage - this is the maximum voltage it can handle continuously. Some specs don't tell you working voltage but rather the maximum voltage just before failure which is a lot less useful. Some specs don't tell you if the voltage rating is maximum or working... so assume its maximum and the working voltage will be a lot lower.