depends on how similar "similar" is. do you have an example?

 

@A Broken man

being practical, for things like this i'd definitely say it's better to be safe than sorry. as it's a first sale, you don't want a grumpy customer going around and making your life miserable. that said, i think you're probably okay unless you're verbatim copying large sections of another site. if you're worried about legal action, i don't know the legal side of this sort of ip case so definitely talk to someone who does if you're seriously concerned, but my guess is that different underlying source codes and having a small portion of overlapping (read: not exactly identical) visual aspects are enough to differentiate intellectual property on two sites.

also, and this might be a stupid question, but why are your sites so similar if your intent wasn't to copy the other site? i don't know how you'd even know about the existence of the other site unless you were using it as a template of sorts

 

Honestly with being in the industry for the past 5 years and working with many laywers in various matters it is very unlikely someone is going to spot you out and target you. They would have to submit a lawsuit and then send a subpoena. All takes time and in that time you can just prolong the hearings. I would not recommend it but to be honest with you the odds are ever in your favor ha