There are many times where it makes sense to file an RCE. Sometimes, however, it is not the cost of the RCE that is undesirable, but the negative affect on patent term adjustment (PTA). 35 U.S.C. § 154(b)(1)(B) provides a 3-year limit on the pendency of an application (beyond which the applicant earns an adjustment), but only in certain circumstances. One of the main ways applicants lose out on the extra time they would otherwise have earned is by filing an RCE. While we will save the intricacies of PTA for another post, here we focus on all some ways an applicant can avoid an RCE. While some of these are not necessarily lower cost options, some are.

Traverse restrictions and petition them if needed. If you have a final rejection but desire to make amendments, one way to get a new non-final is to win a petition against a restriction. If successful, the examiner must examine previously un-examined claims, thus requiring any new action to be non-final.
Look out for improper final rejections. (e.g., see here). For example, a new rejection for an un-amended claim (even just one), or a failing to take notice of applicant’s arguments. Whatever it is, even a minor issue can give rise to a chance at further amendments as a matter of right without an RCE.
Take up an appeal, even if it is for a narrow, unimportant claim as you can often force a re-opening and thus a new non-final action providing a chance for amendments.
Set the case up for #3 on the very first Office action response. Add layers of back-up positions in the dependent claims, and consider including declaration evidence on the first action response. One of the most important things that avoids RCEs is being ready to appeal on the first final, and filing a strong appeal in such situations.
Know your examiner’s tendencies from the first action (examiner statistics).
Look out for errors that fail to give the applicant adequate notice of the grounds of rejection. For example, the examiner may cite the wrong reference, or skip one of the dependent claims in providing reasoning. Such errors can be used to advantage in obtaining another non-final rejection.
Utilize the AFCP program (obviously), and do not be afraid to push back if an examiner states that the program provides insufficient time. For example, if the only issue remaining is one of clarity and the examiner says that an amendment cannot be entered because it requires further searching, consider reaching out to the supervisor.
Utilize examiner interviews on the first action to avoid the final rejection in the first place (obviously).

This is not an exhaustive list so feel free to comment and provide other ways in which you have avoided an RCE in your practice.