There are two issues - one is a requirement for citicenship called "continuous residence." If you have been outside of the US for more than 365 days, then your continuous residence is broken and you must start counting 4 years and one day before you accrue enough residence again to file for citizenship. So, that should not be a problem since it has been more than 4 years since your last extensive trips. The second and more important issue is whether you abandoned legal residence, which can happen if USCIS does not think you made the US your primary residence. There are a number of factors which can indicate abandonment, such as amount of time spent outside of the US. You should have your history as legal permanent resident and the time you spent outside of the US thoroughly evaluated before you begin the naturalization process to determine if abandonment occurred.
The previously posted response to your question contains important information. Addtionally, note that your re-entries into the U.S. as a Lawful Permanent Resident constitute may constitute official recognition of your continued LPR status.
It will be important for you to get a careful analysis by an immigration attorney of your absences, re-entries and related matters in order to determine naturalization eligibility.
[Note: Consistent with Avvo policy, this communication is intended as general information and not as specific legal advice, and this communication does not create an attorney-client relationship.]
David N. Soloway
Frazier, Soloway & Poorak, PC
1800 Century Place, Suite 100
Atlanta, Georgia 30345 www.fspklaw.com
404/320-7000 1-877/232-5352 firstname.lastname@example.org