Always thank them and look sincire. That can't hurt. Do consider it thoroughly, and when possible, show them you acted upon it, for example in your next task, when giving an update, give it in such a way than mentions said advice, even if you took another path, and explain you considerations then.

From my experience, people are not interested in the best professional outcome as much as they are interested in having some meaning, weight or control. Use it to your advantage to get ahead

If the advice was garbage and you know it, try to explain why it was good advice "although I had to do x y since the advice is more fitting if we were dealing with a b"

Listen to them, and go "okay". Then if it was helpful, follow the suggestion. More often than not, though, the advice is not helpful. I'll still listen and go "okay", and then go and do whatever it is that I thought was best.

Painful truth is that I am not an expert in everything. I don't know everything. Even having reached middle age, I've not experienced everything. But by listening to those around me, I can often learn something. That thing may not always be what the advice giver intended, (often it's "This person is an idiot") but learning is good.

The most important piece of information you can ever learn is "Where can I find more information?" Occasionally it's the annoying asshole that keeps giving unsolicited advice.

from a, a coworker and b, a manager

A coworker and a manager at your company gave you advice about your job?

If that is the case, you should take it seriously. Make sure you know why they think their suggestion is better than what you are doing. You don't know everything, there is a darn good chance they are trying to make you better at your job.

If it isn't about your job, you should still make sure you know why they think their suggestion is better than what you are doing. Other people do know things you don't.

I get a little triggered by unsolicited advice as I'm a survivor of narcissistic abuse and, for me personally, it was weaponized as a means of control, destructive criticism, manipulation etc. In general, I tend to take it as a sign that whoever is giving it isn't a good fit for me in a friendship/relationship paradigm. In personal relationships, I find it is almost always intrusive, disrespectful, and/or harmful to the relational bond.

However, a professional context can be different. Unsolicited advice from a manager could be an attempt at coaching/mentoring and I would give it consideration. If it's coming from a coworker in my field with more experience than me, who I also respect, same response as above. A coworker in an unrelated department who I don't respect? Ignore advice and make an internal note that they are likely not my kind of people.