About 350 years.
Deborah (Judges ch.4).see also:more about the Judgesmore about the Israelite prophets
According to tradition, the era of the Judges lasted about 365 years. See also:http://judaism.answers.com/jewish-history/timeline-of-jewish-history
She lived in the era of the Judges, and she was born in the 10th century BCE according to traditional chronology. See also the related Link.Timeline
The period of the Judges doesn't have any special meaning. The book of judges is an historical account of the nation of Israel after the death of Joshua and before the reign of Saul, the first king.
1) They were attacked repeatedly. See Judges ch.4, 6, and 11 (for example). 2) There were some of the Israelites who dabbled in the idolatry of the neighboring nations, thus putting the future of Judaism at risk. See Judges ch.2. The Israelite Tribes were organized into a loose confederacy during the Era of the Judges and while they generally retained friendly relations between each other, they did not rise to each others' defense naturally in response to foreign threats. As long as enemies made sure to pillage only one tribe, they usually could not expect a unified Israelite response. The anomalies during that period occurred when the individual Judges were able to convince several tribes to pool resources and attack the pillaging neighbors. At this period in history, thankfully, the Israelites did not have to contend with massive empires like Egypt or Assyria which could have easily overrun the Israelite confederacy (assuming no Divine miracles).
There are three women who play prominent roles in the book of Judges: Deborah, Jael, and Delilah. Deborah is a prophetess and judge who leads Israel in battle, Jael kills the enemy general with a tent peg, and Delilah betrays the hero Samson. The focus on these women reflects the sociopolitical instability of the era, as their actions highlight the unconventional and often violent ways in which power was wielded in a time of chaos and lack of central authority.
The books of Judges cover a period of about 325 years from around 1380 to 1050 BCE, focusing on the time of the Judges in Israel. The book of Ruth, on the other hand, is set during the time of the Judges but specifically focuses on the story of Ruth and her mother-in-law Naomi during a shorter period of time.
Eli and Samuel were the last two judges of Israel before the era of the monarchy began.
If you're asking about the era of the Book of Judges, the implication of their role is that the Israelites always can benefit from strong leadership. The Judges not only led the people in a few instances of battle, but they also supervised the nation to prevent any incursions of idol-worship. This is why it was only after the death of a given Judge that some of the people began to dabble with foreign gods (Judges 4:1).See also:More about the Judges
1) The period of the Patriarchs. 2) The period from Moses to Samuel, most of which consisted of the era of the Judges. 3) The period from King David until shortly after the First Destruction, most of which consisted of the First Temple era. For (traditional) dates, names and much more background information, see the attached Related Link.
At the close of the era of the Judges, the Israelites asked for a king. See also:Choosing a king
No. The era of the Judges ended precisely when Saul was made king by the last of the Judges (Samuel). See also:The JudgesThe KingsSamuel