At MBSC we have 1.25 lb plates and dumbbells in 2.5 lb increments for exactly this reason. Female athletes or young athletes must be given the chance to improve. Often their coaches are older and stronger and forget something simple. It's not how much weight you increase by. It's what percentage of the total load that weight increase represents. Confused?
Think about this. If an athletes benches the 45 lb bar for 10 reps and then moves up by 5 lbs what is that increase as a percent? It is actually over 10 percent. Four and half pounds would be ten percent. Five lbs is a huge jump. In the early neural stages of strength training/ motor learning this might in fact be possible but would certainly not be considered good coaching. Now imagine an athlete who bench presses 225 x10. Would you jump ten percent to 245? Any experienced coach knows they would not. Stronger athletes routinely add five lbs per week. This is an increase of about 2%.
Even with 1.25 lb plates we may still be overreaching for our younger athletes and females. This is why we have 15-25 and 35 lb Olympic bars, dumbbells in 2.5 lb increments and 1.25 lb plates. Use your small plates and use them intelligently to create lasting progress.
PS- Also, choose warm-up sets well. For three sets of five think warm-up first, heaviest set second, heavy set minus 5 lbs third. This means if the goal is 85x5 think 65x5, 85x5, 80x5.
Next time an athlete asks you to pick weights, think percentage, not poundage.