Don't Add a Captcha To Your Form Unless You Have To

I come across too many web forms which include a captcha element, one of those captchas where you have to type in the squirly characters, I know the site admin added it in hopes it might thwart spam bots in the future. These captchas add friction to users. Most of the time it's an unnecessary friction. I have had my own forms without captchas and had no problems with spam bots. I simply added an invisible textbox to the form. In my code I check and see if the submitted form had this field filled. If it did,  I knew it was done by a bot. A user couldn't see the textbox so they couldn't have entered anything. I wish more web sites used this little trick which doesn't cost anything to web visitors in terms of extra work.

Then if you think you are dealing with a smart bot which "knows" it's invisible and keeps it blank, then you raise antispam defensive measures and add a captcha. Don't add it until you actually have a problem and be prepared to switch quickly to the version of the form which has it. It could be as simple as renaming the current form file and renaming the new one to the working one. Few seconds of work. Don't add a captcha just because other people are doing it or because it's a standard thing to do. It's not. It's being abused. A good usable should be as minimal as possible and captures the absolute necessary information. It's annoying to use a captcha specially if the characters are hard to decipher and the user has to keep refreshing the captcha image until they get a good one. If you're using one which is inaccessible to the visually impaired, you just blocked a section of the web population. There are other forms of captchas where it's an easy click like clicking on a "I am human" checkbox. Some use drag and drop. Minimal effort is your goal. 

If your website gets little traffic, spam bots might not even know you exist. So don't assume that once you put a form online, you'll be bombarded with spam the next second. Use the invisible form element trick, then move up to using a minimal  friction captcha.