I got some emails about job vacancies, both from recruiting agencies as well as directly from the hiring employer. I haven't been in contact with them before, so I believe they got my contact information from my profile on a job portal.
Do I need to reply to all of their emails? I want to maintain my image with them as I found they may become my future employer.
You don't HAVE to do anything, it's totally up to you.
There is not a lot of point in getting involved with the unsolicited stuff, this just spreads your email around and ends up with a lot of spam. It's better just to focus on direct employers and leave out the recruiters.
If you're interested in the job, absolutely.
If not, for either you could ignore them, but:
It would be polite to respond to the direct employer thanking them for the offer but politely declining. If you believe they might have something that's more suitable for you, you could add that too - they might ignore it but no harm in keeping your name on their minds.
Regarding the agency, if you trust them (i.e. it's not just spam) and are keeping an eye out for a job, you could respond to the mail and tell them what kind of positions you are interested in. They may respect that and only send you mails for those kinds of jobs in future (which is good for you). Or they might not, in which case just ignore future mails from them (or redirect them to your Spam folder)
Do employers/recruiters answer every single unsolicited email? No. You shouldn't feel obligated to respond to them all. If the position sounds interesting there is nothing wrong with responding even if it is just to say you're not actively looking for another position right now. If you're interested enough where you think they could lure you away from your position feel free to ask for more information.
The biggest take away here is don't feel obligated to respond. Just know if you don't you're not likely to get a response in 6 months when you're ready to start looking for a new job.
