It's completely pointless and in fact counterproductive to do so many solves with bad habits. If your purpose is not to let new concepts/ideas/methods/algorithms sink in, doing >100 solves is pointless in my opinion. It only gets you even more used to the bad habits you already have.
The purpose of practice is to get into good habits - to get them to become second nature. If you don't have such a goal in mind, practice is not going to help you a lot. For instance, if you're going to do U3 or U4 or even U5 moves to recognize PLL everytime, doing 500 solves is only going to make you more dependent on that bad habit as you get more and more used to doing it.
You always need a goal in mind for each practice session. Tell yourself something like "this practice session, I'm going to make sure I don't pause for more than 1 second between each F2L pair" or "this practice session, I'm going to make sure there is absolutely no pause between my cross and the first F2L pair." Keep reminding yourself of that throughout the session. Like I said, the purpose of practice sessions is to get yourself to improve, consciously. In my opinion, sitting there cubing mindlessly and just hoping that you'd improve is a waste of time. Sure you'll improve that way too, but you should also know that having a clear goal in mind and always being conscious about it is definitely going to make you improve more than just cubing mindlessly.
The final goal of practice is to get you to have no faults in your cubing form and technique so that you can reach your maximum potential without having to think about it; so that good cubing habits becomes second nature; so that you don't regret doing an unnecessary cube rotation that made you slower by a split second; so that you don't regret doing an unnecessary AUF that made you slower by a split second; so that everything about your cubing practices are as humanly optimal as possible for the scramble you were presented and you have no "regrets" about the way you went about solving it. In other words, the purpose of practice is to get you to do a solve and NOT go "it could've been faster if I..." when you're done.