We do have term limits. They are called "elections." That said...

Vital Statistics on Congress
http://www.brookings.edu/vitalstats

The Rising Incumbent Reelection Rate:
Whatís Gerrymandering Got to Do With It?
John N. Friedman and Richard T. Holden
June 26, 2007
http://www.mit.edu/~rholden/papers/In...

Reelection Rates Over the Years
Few things in life are more predictable than the chances of an incumbent member of the U.S. House of Representatives winning reelection. With wide name recognition, and usually an insurmountable advantage in campaign cash, House incumbents typically have little trouble holding onto their seats—as this chart shows. US House Re-election Rates 1964-2016
https://www.opensecrets.org/overview/...

However, that all having been noted, consider what happened in Michigan when term limits were enacted in 1992 (effective 1993).

1. The natural progression from the state house to the state senate continued. Representatives who were term-limited in the lower chamber ran for the senate, and some of those open seats were open because of term limits, of course.

2. Redistricting is a natural result of populations changes, even when gerrymandering is not engaged. So, elected representatives did not even need to move their homes, though some did move to nearby communities in new districts.

3. I was surprised when my Lansing district went from Party A to Party B, but the same people answered the phone. The staff runs the office and knowledgeable politicians keep some, much, or all of the staff when they take over the office.

4. That leads to the fact that if you start dumping your elected officials, the balance of power shifts to the administration, i.e., the bureaucracy. After all, they become the only ones who know what to do and how to do it.

In every state, you will find some districts without opposition to the incumbent. On average in the USA, 30% of state house seats are unopposed. Here in Texas it is over 60%.
https://ballotpedia.org/Texas_House_o...

Moreover, at the state level in 2014: "Incumbent turnover, the combination of legislators retiring or losing in primaries, shifted back down to levels seen in elections four years prior. Nevertheless, 131 major party incumbents lost a primary. Thirty-six percent of those were Democratic seats; 64 percent were Republican." https://ballotpedia.org/State_legisla...

Remember that "all politics is local." You have more control and more power at the local level. You have a voice in city hall that you may never have in Congress. Having run for office a couple of times, those "dog catcher" posts are accessible.

Personally, all other things being equal, I prefer that elected officials have some maturity in office. It takes time to figure things out, to get to know people, to understand issues.

Finally, a friend of the family always voted for the incumbent on the theory that that politician already lined his pockets. You elect someone else and they have to line theirs anew.