Risks with high arbitrages
Trying to go after the highest arbs all the time is usually not a good strategy in the long run. The reason is that high arbs have a higher risk of including odds that are bookmaker mistakes, or so called palpable errors. Sometimes, the bookmaker will even void your bet. While they do pay you back your stake, it can still cost you if the voided bet was the winning one. Betting on smaller arbs more frequently will result in a lesser risk for palps and you might also be limited less quickly.
Also, as a guideline, double-check that the arb you bet on is correct and that there hasn't been a market mix up. Be extra cautious when it comes to arbs over 10%. Also, check that the teams you are betting on are playing in the same tournament before placing the arb.