[quote]R42: I'd arrive when the room was empty, borrow clothes, cash and my father's driver's license (we look enough alike I could pass for him),
It's not like any of those 'borrowings' would not be noticed. You would have altered the past which produced you, creating a paradox. We don't empirically know what would result from that. It might zero you out completely, so that the 'you' who went back never existed, and thus couldn't 'borrow' the money and clothes. The past would remain unchanged, but you would no longer exist from the moment you departed on your time-travel trip to the past.
An alternative theory would be that you could travel back and make these changes, but that all subsequent history would be different, and you would find that you could never return/find your way back to the reality from which you'd come; you would become 'orphaned' from your own timeline.
To illustrate this theory of time travel, let's take 'George' from Pal's version of 𝐓𝐡𝐞 𝐓𝐢𝐦𝐞 𝐌𝐚𝐜𝐡𝐢𝐧𝐞 (1960). George boards his machine and leaves his home on the evening of Dec. 31st, 1899, traveling into the future. He makes various stops on the way, and eventually winds up visiting 802,701 CE, finding a society bifurcated between surface and underground dwellers. He has his adventure (you've seen the movie, right?), and then returns to Friday, January 5, 1900, in time for the dinner party he'd scheduled with his friends that past New Year's Eve. He tells them his story, and gives Filby the flower Weena had given him. Three of them scorn his story, and refuse to believe him. Incensed, he grabs three books from his own bookshelves and sets off again into the future. Filby and Mrs Watchett presume he's gone back to 802,701 CE, to reunite with Weena outside of the Sphinx, and to "help the Eloi build a new world." And so the film as we know it ends.
But search as he might, George never again finds Weena, or the Eloi as he had left them, free of Morlock rule. His return to 1900 and telling the story to his friends altered all subsequent future events. Weena and the Eloi with whom he shared an adventure are now gone, part of an 'orphaned timeline' which only George remembers. They can never be recovered. Another world, with other people and circumstances, occupy the place they once did. We can only speculate what fate met George, for, as the novel puts it, "as everybody knows now, he has never returned."
As far as my own attitude towards the imagined possibility of time travel, I would not do it. If there were some sort of magnum opus detailing the issues of time travel (𝐃𝐨𝐧𝐧𝐢𝐞 𝐃𝐚𝐫𝐤𝐨 2001 postulates a book, 𝑇ℎ𝑒 𝑃ℎ𝑖𝑙𝑜𝑠𝑜𝑝ℎ𝑦 𝑜𝑓 𝑇𝑖𝑚𝑒 𝑇𝑟𝑎𝑣𝑒𝑙, written by one Roberta Sparrow), in order for it to offer important practical advice, the first page of the book would contain a couple of rules. Rule Number One would read "𝐃𝐎𝐍'𝐓!", and Rule Number Two would offer, "𝐇𝐄𝐄𝐃 𝐑𝐔𝐋𝐄 𝐍𝐔𝐌𝐁𝐄𝐑 𝐎𝐍𝐄." Breaking these rules and engaging in time travel would always result in some form of self-destruction, or at the very least, the loss/destruction of everything and everyone you ever knew.