I appreciate mint flavor in salads and I have been successful over a number of years in keeping my spearmint plants growing. Generally, mint should be contained because it can become aggressive and take over other plants. I’ve kept my plant in a flower bed and dug it up every couple years and moved it to a new location when it gets root bound.
This past summer I had mint growing in a tub close to the hose so that it would be easy to water whenever the tap was turned on, as it prefers a moist soil. We were away and the tub dried out. The mint still lived but it was not healthy. I had some mint growing in a shadier spot in a flower bed and it flowered and went to seed. I love the tiny blue flowers in summer that attract so many bees. At the end of the summer I cut the plant down and it has since shot up, giving us young fresh mint leaves to pick.
This summer mint seeded itself in some gravel in a shady spot and this mint was still young at the end of the summer. Mint will grow from small cuttings from the root or the stem so it often appears in various spots in my flower beds. When I get too much of it, I just cut it back or pull up the roots and discard them. In my garden, by pruning some plants and allowing others to grow, young leaves are available almost year round.