No lifetime limit. A deductible IRA is subject to eligibility phase out. Taxes on earnings are deferred until withdrawn. Qualified withdrawals are taxed at the student's rate. State tax varies.
Qualified withdrawals are exempt from federal income tax.
State tax varies. Withdrawals of contributions are allowed anytime. Qualified education expenses are not subject to penalty. Qualified education expenses are not subject to penalty. Earnings are taxed as capital gains or ordinary income when investments are sold or dividends are paid.