Just a few thoughts from someone who has been through the criminal justice system-
Probation- If you are placed on probation for a weapons related crime you will be prohibited from possessing any "deadly weapons" for the duration of your probation (years), this includes all firearms and knives other than kitchen knives. If you are required to have knives for your job, exceptions will be made but do not expect your probation officer to be generous in what they consider to be acceptable. Forget about carrying a knife or having non-kitchen knives in your home. There will also likely be other restrictions on your freedom depending on what type of probation you are on. You might lose your fourth amendment rights against warrantless searches (cops will be able to search your home, vehicle, and person WITHOUT a warrant). And you might be required to ask for permission to leave your county for any reason.
Probation and court fees (which you are required to pay) can be a few thousand dollars or more. And then of course there are any fines you might receive.
Lawyers (both public defenders and "paid" lawyers)- Some are good and will do everything possible to fight for you, but some really suck and all they want is to be done with your case so they can move to the next one. Even paid lawyers, ones you have paid thousands of dollars to, might sell you out just to make their lives easier. Once your check clears, you're just a bother to them and they want to be rid of you as quickly as possible.
A bad lawyer will take advantage of the fact that you are ignorant of the law and how the system works. They will tell you what THEY want you to know. They will advise you to do what THEY want you to do. They will pressure you to take the first deal that the prosecutor offers because that will end the case quickly (less work for them). Their goal will not be to get the best possible result for you, but instead to make THEIR life easier by putting the least amount of time and work into your case.
From everything I've seen, it's almost impossible to replace a public defender with a different public defender. If you want to replace a PD you have to hire your own lawyer.
Plea Bargains- One of the first things I learned after going through the criminal justice system is that you NEVER take the first deal that is offered by the prosecutor. Your lawyer (if they are a bad one) will want you to take the deal and might say anything, even lie to you, in order to convince you to take the deal. But among experienced offenders/inmates/criminals, the first deal offered is called "the IDIOT DEAL", as in, only an idiot would take it. And that is often what the prosecutor is hoping for, that the defendant will be dumb enough to take the deal. The reality is that a prosecutor will often offer an "idiot deal" despite knowing all along that they don't have a case. And in many cases, when a defendant refuses the "idiot deal", the prosecutor will drop the charges entirely because they don't have a case to take to trial. There is a lot of trickery and dishonesty involved in the criminal justice system. Just as your own lawyer might lie to you in order to convince you to take a crappy deal, a prosecutor might try to get you to plead guilty even if they know that they have no case. Sad but true.
The general rule among experienced criminals is, refuse the first deal and DEMAND a trial. What this does is, it forces your lawyer to fight for a better deal, or fight to have the charges dropped, because your lawyer doesn't want to go through all the time and work of a trial (unless you're paying them by the hour). If the charges are dropped, great. If they aren't dropped, what usually happens is, right before the trial starts the prosecutor will offer the "sweetheart deal". The "sweetheart deal" is the very best deal that the defendant is likely going to get and it will be far better than the "idiot deal" that was initially offered. The prosecutor offers the "sweetheart deal" in order to avoid going through with the trial, or because they know that their case is weak.
If I were in your shoes, and if I could afford it, I would seek out a private attorney. But whether I hired my own attorney or stayed with a PD, I would refuse the first deal and DEMAND a trial. But that's me, and it's something I learned the hard way as both a defendant and a convicted felon.
As for your case, I'm curious to know the circumstances of your arrest. Specifically, if you were stopped by a cop solely because he saw the pocket clip of your knife, then I can't help but wonder how he could say the knife was "concealed"? How can they call a knife "concealed" if it was visible? But I guess that's a matter to be resolved in court.
Good luck to you.