This may seem pretty common knowledge but you really shouldn’t use your primary email address for sites that are not relevant or those which look spammy.
Chances are the in-built spam filter in most email providers work well but that still leaves your primary email address exposed to spammer’s list.
One solution is to use a different unrelated email account purely for sign-ups to sites everywhere so that all spam received is within that email inbox.Still you need to login to that email account once in a while else it gets deactivated and can’t use for further registrations/site sign-ups.
Another one is using a disposable email id,disposable as in use once and throw away.
I found 10 minute mail to be quite handy for this.Check it out here.
Once you visit the site,a random email address is generated which is valid for 10 minutes(if you want to extend to another 10 mins and so on,click the Give me more 10 minutes link there.)
The email addresses assigned are difficult to comprehend or remember but they very well serve the purpose of receiving messages and being disposable after that.
Hope you find this service useful,I certainly did.