Electronic – life tolerance of a resistor

Monte Carlo analysis and worst-case is usually the way this is done, exactly as the linked article describes. For Monte-Carlo you don't have to change your components by hand, just run the Monte Carlo sims and the simulator will automatically change the components based on your Tolerance field. You have to run enough cases to get a statistically significant result, and you can calculate how many runs you need for a given confidence. Worst-case requires a little more work and knowledge of how the circuit works, but the linked article explains that as well.

If you're measuring the resistance in similar conditions to what it will experience in the circuit, then yes, you can use either resistor. If the circuit is going to heat up the resistor by 70C, then maybe not. Resistors, capacitors, and inductors can all be made out of different materials, each of which has its own properties. Here are some things that might matter aside from the component value and tolerance:

• Power handling
• Parasitic resistance, inductance, and/or capacitance (important at high frequencies)
• Temperature coefficient
• Max operating temperature
• Max soldering temperature
• Operating lifetime (very important for electrolytic capacitors)
• Breakdown voltage and polarization (for capacitors)
• Matching of multiple components (sometimes more important than tolerance)
• Electromagnetic interference and compatibility (radiation/sensitivity)
• Noise generation
• Package size and weight (often related to power handling and parasitics)
• Reliability of the supply chain

Usually only a couple of these will be major concerns in any particular application. For example, in audio systems, you're very concerned about noise. In automotive and aerospace, a high max operating temperature is required. In high-frequency design, parasitic inductance and capacitance are a big deal. For low frequency, low power, low precision circuits, just about any component will do.