after a firm extends a TC offer, what is a 'normal' time frame for someone to get back to the firm with a definite yes/no answer? I have several interviews going on and I don't really want to commit before I get answers/offers from the firms I interviewed at. if the TC starts more than a year later, can I tell the firm I will weigh my options and give the firm a yes/no answer in like 6-8 weeks? (not big 4, just small firms)

will i incur any penalty if I accept a TC offer from one firm (small firm) then tell them a few weeks later that I have decided to accept a TC offer from another firm? ofc it looks bad but are there any other downsides, or should i just avoid doing this as much as possible