For me i prefer mix. Low bets with low price at first and i will change my strategy based on what ive got. If i win, i change to high risk high price. If not then i continue to that lowkey betting.
As per money management principles (if you are following it even for your gambling beyond trading and investments), you must always stick within same level of bet because if you win 10 times in small bets and you may lose all the profits in one single bet if you keep on increasing your bet. Sticking with same level of bet amounts is always eliminating excess risk levels. If you are about to gamble along with calculated risk then you should not mix bets while you are gambling.
I also rarely increase my bet amounts but it is basic human nature that everyone wants to bet higher hence increasing it slowly over the time but I do see these are all just the sign of we are getting greedy.