Couples in healthy relationships have a "thermostat." They enjoy the comfortable "72 degree" feeling and they work hard to protect it. In the summer, if the thermostat waited until it was 90 degrees outside to kick in, it would take a long time to get the temperature back to 72. Likewise, healthy couples use their thermostat to recognize when their relationship is getting heated and deal with problems quickly instead of letting them build up into a 90 degree argument that could take days to recover from.
If you want your relationship to stay consistently loving and respectful, check your thermostat regularly. Know what the temperature of the relationship is, and do something sooner than later to correct the problem. It's so much easier to have a ten minute conversation about an issue that has just occurred versus an extended argument over problems that have cropped up for days or weeks at a time.