The question is more for software developers.
Some jobs requires 8 hours per days (hourly contract).
From my experience, I can work(programming) 5-6 productive hours (in sum) not including breaks.
Can someone tell his experience about this type of jobs?
And what is your daily limit?
For me tracking 8 hours of programming kind of not realistic (if you are really working).
Some programmers can work for 18 hours straight with only a few minutes for breaks, during a day.
Some programmers can only work for one or two hours in a single day.
I have been both.
I don't think very many programming jobs "require" a specific number of hours per day. Most project owners simply want the work to get done. They know that a programmer isn't guarding a door while the jewelry store is open. So 8 hours a day would be an unusual requirement.
But if 8 hours a day IS the job, and you can only do 6 hours a day, then it means you are not a good fit for the job. Some jobs require a freelancer to speak fluent Japanese. I don't speak Japanese, so I would not apply to those jobs.
Keep in mind that the default maximum number of hours per week for an Upwork contract is 40 hours per week, which divided by five equals 8 hours per day. If you see that, it does NOT mean that a job requires 8 hours per day. It just means that the client did not change the default setting.
Actually one of my clients ended a contact because in the end of the month I didn't reached 160 hours.
But if we compare to office developers, they not actually work 8 hours.
Maybe this client was is exclusion, and measured performance by tracked hours.
re: "Maybe this client was is exclusion, and measured performance by tracked hours."
This was an exception.
Most freelance programming jobs are not going to evaluate a freelancer based on the number of hours they log and end a contract if there aren't enough hours.
You will lose money when you take jobs that don't allow for manual time. I avoid clock time as a rule. You may be better off getting the client to convert to a flat fee. That involves risk the client will not pay but that provides a higher potential margin as an outcome, sir. Think about it. If you are going to bid software deals, you are in a business where the pricing model is a race to the bottom. Competing on the basis of price is an almost certain guarantee of a future of declining earnings for more hours of work.