If you had put in your bike 7 speeds cassette. And you have two cassettes 12-23 and 12-28 which cassette you choice and why.

If you have them, try both - then decide.
IMHO - a dumb question.

Maybe a little more detail will help. What kind of riding do you do, hills, flats, fast club rides, etc? What chain rings are you running. Are you a spinner or masher?

My Tommasini has a 7 speed freewheel in the back. It originally came with a 13-23, which I swapped out for a 13-28. Why? Simple reason - I live on a pretty steep hill, and my front crank is a tight spaced 42-53 Campy Super Record. When I started riding again last year after a 2-decade layoff, when I got WAY out of shape as well as much older, and I couldn't get up the hill I live on with the original gearing my bike had, from back in the day when I was 20 years younger and over 50 pounds lighter. Since the whole bike is Campy Super Record, I didn't want to change out the crank to a compact, so my only other option for hill gearing was a bigger cog in the back. So I ride a 13-28 now, instead of a 13-23. And I'm back in much better shape, but I still prefer the wider spacing in the freewheel. The small gears are 2 tooth jumps, but the last couple few jumps are 3 and 4 tooth. 13-15-17-19-21-24-28.

Thank you for your answer. 13-28 cassette do you feel big gaps bettween the gears or not? I mean some people want 12-23 cassette because say is keep good cadence. But me i say you think good 13-28 is much better. i replace tires in one man bike and had 7 speeds cassette 12-28. this man have one bike cannondale R300 have the 52/42 and the 7 speeds cassette 12-28. I have the same bike but mine i buy from pawn shop. the man bike have original wheels and groupset. My bike had different wheels and i change the crank to 53/39 and i put 9 speeds cassette 12-25 but now i am thinking put 13-28 cassette. 53/42 crank is working better for you? is better than crank 53/39?

I don't mind 2 tooth cog jumps even at the small-cog end of the cluster. Sure, 1 tooth is nicer, but I can vary my cadence 5-10% without difficulty. Yes, I would generally find a 53-39 crank to be more useful than a 53-42 crank, but Campy didn't make Super Record with a small enough bolt circle in the early 1980s. Later, they did. I've considered replacing my Super Record Crank with a Chorus 53-39 crank, but frankly, given the terrain that I generally ride that bike, I don't need it, since I'm in better shape now, and my existing gearing on that bike covers most of the terrain I ride. I also own other bikes, one of which has much wider range gearing (9x3 including a front triple that covers 51-39-29) and if I'm riding MAJOR hills, I ride that bike, but less than 20% of my rides put me out of my comfort zone with the narrower range Tommasini. Again, multiple bikes. But if I only had one bike, and I rode very hilly terrain, I would not use just a 7x2 drivetrain, I'd use at least 9x3. That's enough gears for both narrow spacing and wide range.

thank you for your answwer. All my bikes have double crank 53/39. All bikes is road and one TT. I have one mountain bike the crank is was 48/38/28 but i put road bike crank in this mountain bike 52/42. I have ride the bike in hills but in flat trail no have ride yet i want see if with that crank is go be fast like road bike.