For primary fermentation, these are fairly typical bucket & carboy sizes. Once the fermentation starts, you'll start generating CO2 which blankets the top of your beer as it is more dense than oxygen. This prevents the oxidation process which causes the stale cardboard flavor to appear in your beer.
You may want to purge these sizes with CO2 if you plan to use them for secondary fermentation. You don't have the advantage of high CO2 output during the secondary so you're at a higher risk for oxidation with a large headspace.