That being said, when you do receive, or even anticipate receiving an offer, you should have already prepared yourself mentally for your decision and be ready to act swiftly and accordingly. It is fine, and even highly recommended, to review your offer terms, the new firm’s benefits (especially moving expenses and pro-rated bonuses, if applicable), and to ask as many questions as you need to in order to resolve any issues you might have with the offer terms.
On the other hand, once you have satisfactory or at least conclusive answers to your questions, and the terms are all there on the table, it is much better from an optics perspective to accept the offer and move forward quickly and eagerly into your new position. In other words, you want to start with momentum for yourself, and show your new firm and the partners that you are excited to be there. After all, even though you have interviewed there, and met and spoken with many of the attorneys, the offer acceptance stage is really your first impression to the firm as a new member of the team. Your initial enthusiasm and excitement can go a long way towards making the transition smoother both from a logistical perspective, and in terms of getting immediate quality assignments from the partner team, which will help set you up for near- and long-term success.
Hesitating too long, or requesting multiple extensions for the offer deadline without specific and good reasons, can make it appear to a firm as if they are not actually your first choice, or if you have some hesitation to come on board, both of which can unfortunately result in less than a positive first impression. It also puts the firm in a tough spot, because they likely paused their interview process once they extended the offer to you, and if work is busy and they need immediate help, the partners can become annoyed with any unnecessary delays.
Ask the questions you have, get the answers you need, but when you get to the point where you have all the necessary information and you know what your decision will be, it is better to inform the firm of that decision as soon as possible and start off on the right foot, with energy and enthusiasm.
As always, best of luck with your search!