OP, your question is impossible to answer, because EVE is an open-ended game. It’s not like you’re queuing for “PvP matches” (although with the new arenas, lol…) every 15 minutes, and can calculate your average lifespan based on your win/loss ratio.
There are two distinct ways to approach PvP in EVE:
- You PvP “for fun” by your own choice, which means that you have to “fund” the PvP with some kind of income stream, since your PvP is expected to be a net loss.
- You PvP with some kind of profit motive in mind, either by pirating/ransoming targets, fighting as a mercenary, taking POCOs by force, et cetera. In this case, your PvP efforts should result in a net profit, on average, but do keep in mind that in order to pull this off, you will beed a lot of skill and planning.
As a new player, your PvP activities will most likely lean toward the first way, since you will be going through the learning process.
Instead of thinking about losses in purely terms of how often they happen, what you should do is calculate the profits from your income streams, and calculate how much you can lose every day from PvP activities. If you have 10 million ISK to play with, and each of the PvP ops you participate in lasts an hour, then you can take part in said PvP ops for 5 hours using 2-million-ISK frigate setups.