I'll have my first face to face interview soon and I have a few questions. Do I have to accept or reject the offer on the spot or is it okay to ask for some time? How long do you think I should take to reply?
Do I have to accept or reject the offer on the spot or is it okay to ask for some time?
It is OK to take some time to decide. Most (all actually) interviews I've had have been this way.
How long do you think I should take to reply?
It is highly probable that they will tell you by when they expect your answer. You should then make up your mind and decide by that time, so you can convey your answer by the date given.
You will then have until that date to decide among the other offers or options you have lined up.
Some useful posts that you may consider reading, regarding the handling of multiple offers, some with different expected times of response, etc., include:
Do I have to accept or reject the offer on the spot
Offers on the spot are quite rare. Typically you talk to a number of people and they need some time to integrate the data (means "talk about you"). They often run multiple candidates and don't make a final offer until they have interviewed them all and ranked them. Then they will offer in order of the list. It's much more likely that there is a significant time gap between the interview and an offer, decline or simply just nothing. Even if they want to hire you, there is often also a bit of back and forth on the details (timing, comp, benefits, relo, equity, contracts, ...) before the formal issue gets offered Getting an offer on the spot is a clear indicator that you are very strong candidate, so it's a good problem to have.
is it okay to ask for some time?
Yes. One week is fairly normal and can often be extended with the right reasons (and candidate). However, it's better to analyze the situation up front and make sure that you know what your own decision criteria are. If you have done your up front research properly and nothing overly surprising happens at the interview, you should be able to make a decision quickly. Primarily you should take this time to study the details of the offer, carefully read all the contracts and agreements you are supposed and work through any adjustments and/or misalignment.
Blanket Advice: never sign anything that you haven't carefully read and that you are sure you fully understand.
My experience (the Netherlands, Belgium). Normal is one week to think about it, longer might be seen that you're not so interested.
Normally after interview, employer takes one week to decide. After that he sends you a contract, or in person. You take one week to decide/draft changes to the contract (always draft changes, even if they are just secondary. You meetup to sign the contract, or do it digitally. Up to the signing part you can still refuse the job offer (as long as you didn't say anything verbally or writtenly that you would accept the contract).