Elected institutions in the USA, frequency and maximum term
Presidential elections (the executive) - Every 4 years for a maximum of two terms (8 years), or if a vice president has replaced a president over half-way through their term, they are restricted to 10 years maximum
Congressional elections (the legislature; which has two houses)
Senate elections - One third of the senators are up for election every 2 years, serving a 6 year term
House of Representatives - All Representatives are up for election every 2 years, serving a 2 year term
Gubernatorial elections (i.e. elections for the post of governor; state executive) - Frequency and term lengths/limits vary per state (D.C. has a mayor)
State legislatures (mostly bicameral but chambers and names vary) - Frequency and term lengths/limits vary per state
Some additional state-wide elections (e.g. lieutenant [deputy] governor)
Local elections (e.g. mayor, sheriff)