Watch out for sign up bonus!

If a casino gives you a sign-up bonus, it's because it has an interest in doing so. Certainly to keep up with the competition, but above all because it forces you to play longer.
I'll say it again, the casino always wins in the long run, so they want to capture you.
Before taking a sign-up bonus, check what you're agreeing to.
In general, you need to wager 20 to 30 times the amount of the bonus to be able to claim it.
It's huge! You are going to have to bet (for a start at 200 Euros with 100% bonus) from 4000 to 6000 Euros! If you bet 2 Euros of chips, that goes from 2000 to 3000 bets... you are sure to ruin yourself even playing with my method because you do not respect the rule not to play a long time...
Be aware that the money awarded in the bonus is never recoverable (you are not offered this money, it remains in the casino) and the withdrawal of the money won on the bonus is subject to a minimum amount of money deposited (your money) in the casino. Be sure to read the casino contracts on this subject.
In general, taking a bonus adds a whole set of conditions which may restrict the conditions for withdrawing the money actually won.
My advice is simply not to take the welcome bonuses.
To refuse it, all you have to do is either tick the appropriate box when you register, or not deposit anything and contact customer service to cancel it if the bonus cannot be refused when you register. Customer service will do everything they can to dissuade you, but if you play as I advise you to, you will never be able to benefit from the bonus.
An example?
Let's look at a real example whose name I won't mention. It's all modern, accepts French players, in euros and has nice roulette wheels with stakes from €3 to €500 on a single-zero roulette wheel. There's even a display of outings history on colours or odd/even. It's all there except...
Except that you should always read the terms and conditions, because there is a surprise that is unfortunately very common. The site offers a 150% first deposit bonus and says :
"Bonus money is virtual money that cannot be withdrawn". Don't panic, this means that only the winnings from this money will be counted, that's normal. BUT :
The bonus+deposit must be wagered 33 times (with wagering requirements) before any withdrawals can be made.
This doesn't look good. Imagine depositing €150. Yes, the deposit is high because the smallest roulette bet offered, which meets the condition of being able to bet 64 times the initial bet, has a starting bet of €3. The site therefore offers 1.5x150= €225. You therefore need to bet (150+225)x33 = €12375 to be able to withdraw. Stings, doesn't it?
Let's say that in order to win €10 a day, you have to bet €3 or €6 or €12 or €24, etc... The bets go quickly, but if you imagine having to bet an average of €12 to win €1, you'll only be betting 12x10 = €120 a day.
You will therefore need to bet €12375/120 = 103 days to be able to withdraw. That's a bit long and means you'll have to bet more and take more risks.
If you take more risks, you risk losing. If you deposit again, a new bonus applies with a new condition: 50% bonus and 'The bonus+deposit must be played 25 times (with wagering requirements) before you can make any withdrawals.' So it never stops.
By the way, what is this wagering requirement? In general, you're asked to make a minimum percentage bet on certain games, slot machines typically, in order to be able to withdraw. If this is the case, skip it and be aware that it is clearly indicated (albeit in very small print :D).
How to cancel the bonus?
Online casinos are obliged to allow you to opt out of the bonus and therefore obtain more favourable withdrawal conditions.
All you have to do before depositing is contact the site's support (preferably by email, it costs nothing) and say that you want to deposit without getting the bonus. It works.
With the example above (tested it works), this casino becomes eligible for my method. If you deposit €150, you will need to bet 33x150= €4950, which takes 41 days. You'll need to be patient and not play anything other than "common draw roulette", but it can be done.
Now you know one of the 'tricks' to avoid, enjoy the rest of your reading.