Ive done that many times but the poster I quoted said that everyone starts any new character at level 1 regardless of what level everyone else is at. I usually start players in an existing campaign 2 levels lower than the lowest PC. Seems to work.
That's my philosophy too. Plus, they only get starting equipment/gold. If everybody else has a mount, I might consider including that as well, just so they don't slow the party down while they earn the money.
If a new 1st level PC joins a party of 4th and 5th level characters, they just all work together to keep the squishy noob alive long enough to level up.
The way that 5e leveling is designed means that - as long as the DM is providing equal shares of XP to everyone present - the lower level PC will close the gap quickly. That 1st level PC might earn enough XP during that initial session to jump to 3rd level where the 5th level characters are still progressing through 5th level.
I feel like this ground has been tread before. Some tables prefer having all PCs at the same level. Some don't. There is nothing about the design of 5e, however, that makes it a requirement to have everyone at the same level. In fact, the Creating Encounters section of the DMG (specifically the Evaluating Encounter Difficulty passage on p82) indicates that a varied level party is perhaps even expected.
That 1st level PC might earn enough XP during that initial session to jump to 3rd level where the 5th level characters are still progressing through 5th level.
In previous editions a PC couldnt gain more than one level at a time, has this been removed? I havent read the DMG all the way through, there are parts I skimmed and others I skipped.
It just depends on XP. I always tell my players to have the next level prepped when they are getting close, because otherwise their HP and hit dice are the only things that will level up until we take a break. However, if they have everything prepped, they level up immediately.
I suppose allowing players to advance multiple levels at once will work as long as the players are prepared and know the abilities they will gain. I still prefer to limit it to one at a time. Thats one of the old throw ack rules I still use, any excess xp is lost if you exceed more than one level when leveling.