Yes it is good to work your abs and all your core muscles, but I would also throw in some cautionary notes too. The obvious is that you might want to lighten up if you have some residual soreness. And you will probably want to rest entirely if you have pain, and especially any sharp or stabbing pain, which is generally indicative of an injury. Additionally, it is generally a good idea to work opposing muscle groups so one doesn't overpower the other (i.e injury.) So I wouldn't do ab without back, quads without hamstring etc and in some case you may have specific weight ratios one to the other to pay attention to. And in any workout or fitness routine you are going to want to pay attention to proper form and technique.
Having said that, you generally don't progress by continuing to do the same thing over and over. Progress is a function of taxing yourself and recovering through a variety of different exercises and rests. So to see improvement you would want to have harder days, lighter days, and sometimes even days off as well as different levels of intensity and duration built into your programs. This is one reason why you see people working different things on different days, it allows for concentrated focus on the "on" days and rest and recovery on the "off" days.... even if "off" is just a very light day.
The answer is no! But I would advise that you alternate the abs workout - for example one day do upper abs and the next do lower abs, this way you give the previous muscles time to rest and recover which is very important to show progress.