The source's most useful starting point is that coffee should satisfy the person drinking it. Price, origin prestige and a fashionable roast style cannot determine that preference. At the same time, several practical conditions can prevent an otherwise suitable coffee from showing well: stale grounds, poor water, dirty equipment or an inconsistent recipe.
Buy an amount you can use sensibly and check the roast date and packaging. Whole beans allow grinding close to brewing. A valve bag helps release gas from roasted coffee, but no package makes freshness permanent. The best resting and drinking window varies with roast, storage and brewing method, so a rigid two-week rule should not override the condition of the actual coffee.
For improvement, compare like with like. Keep the water and recipe steady when changing beans, and keep the beans steady when adjusting the grind. Clean brewing equipment and follow its maintenance instructions. Neither Arabica alone nor a high growing elevation guarantees a good result; processing, roasting and preparation still matter. A useful quality judgment combines identifiable coffee, sound handling and a cup that meets your own expectations.
The conversation
A good question can make a better brew.